TEST PAPER 1

UNIT 1 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. 1 nanometer = ______ cm.

    1. 10-9
    2. 10-8
    3. 10-7
    4. 10-6

  2. The most important property of nanomaterials is ______.

    1. force
    2. friction
    3. pressure
    4. ductility

  3. For a plane mirror, magnification (m) = ______.

    1. 0
    2. 1
    3. +1 or -1
    4. <>

  4. Blue + Green (light) = ______.

    1. Magenta
    2. Cyan
    3. Yellow
    4. Violet

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. Define : Nanotechnology.
  6. Define : Principal focus of convex lens.
  7. Why does a green leaf appear green ?
  8. Mention the principle of simple microscope.

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. Explain the use of nanotechnology in diagnostics.
  10. Explain : Regular reflection.
  11. Explain : Near-sightedness(no diagram).

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Describe the concept of nanotubes.
  13. Describe subtractive method of mixing of pigments.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Derive mirror formula.

TEST PAPER 2

UNIT 2 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. The equivalent resistance of three resistors, each of 6 Ω, connected in parallel is ______.

    1. 6 Ω
    2. 18 Ω
    3. 2 Ω
    4. 0.5 Ω

  2. Which of the following is not correct for the electrical work ?

    1. W = VQ
    2. W = VIt
    3. W = I2Rt
    4. W = I2RQ

  3. What is the frequency of current used domestically in India ?

    1. 50 Hz
    2. 60 Hz
    3. 110 Hz
    4. 220 Hz

  4. The principle of magnetic induction was given by ______.

    1. Faraday
    2. Galileo
    3. Oersted
    4. Ampere

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. Define : Electrical potential.
  6. What causes resistance in a conductor ?
  7. What is over-loading ?
  8. What is alternating current(AC) ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. State two disadvantages of series connection.
  10. If 300 mA current passes through a lamp, how many electrons will pass through it in 1 minute ?
  11. Explain the work(importance) of a fuse.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Explain the construction and working of a simple Voltaic cell.
  13. Explain the experiment to show the presence of magnetic field due to electric current.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Describe Ohm's experiment OR Describe electric motor with neat diagram.

TEST PAPER 4

UNIT 4 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. Formation of petroleum in earth's crust is a ______ reaction.

    1. geochemical
    2. biochemical
    3. physiochemical
    4. physical

  2. Pyrex glass is ______.

    1. plasticized glass
    2. polymeric glass
    3. heat-resistant glass
    4. opaque glass

  3. Ethylethanoate is ______.

    1. an alcohol
    2. an acid
    3. an ester
    4. a ketone

  4. Which of the following is not an oxidising agent ?

    1. NaBH4
    2. KMnO4
    3. Cr2O3
    4. Fehling's solution

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. Define : Rate of reaction.
  6. State the Law of Mass-Action.
  7. Who prepared Portland cement for the first time ? When ?
  8. What is formalin ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. Explain : Molarity.
  10. Describe manufacture of lime.
  11. Show that the H atom in the -COOH group has acidic nature.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Describe Ammonia-Soda process to obtain washing soda.
  13. Write chemical properties of formaldehyde giving chemical equations. OR Describe preparation of polyamides(nylon) and give its two uses.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Write a detailed note on pH.

TEST PAPER 3

UNIT 3 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. What is used generally as a connecting material in solar panels ?

    1. Silicon
    2. Silver
    3. Selenium
    4. Germanium

  2. ______ invented artificial radioactivity.

    1. Marie Curie
    2. Berkley
    3. Lord Rudherford
    4. Maxwell

  3. The mass of earth is ______ times the mass of mercury.

    1. 10
    2. 14
    3. 18
    4. 22

  4. Each nakshatra is an angular region of about ______.

    1. 15° 30'
    2. 14° 40'
    3. 13° 20'
    4. 12° 30'

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. What is the wavelength of visible light in meter ?
  6. How is charcoal obtained from wood ?
  7. What is corona ?
  8. What is celestial sphere ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. Mention two advantages and two limitations of solar cooker.
  10. Explain the theory of formation of our solar system.
  11. Explain the installation of artificial satellite by space shuttle.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Mention six characteristics of ideal fuel.
  13. Write a note on asteroids(six points).

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Write a note on Nuclear reactor with a neat diagram. OR Write a note on galaxy.

TEST PAPER 5

UNIT 5 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. During electrolytic reduction, ______ acts as reducing agent.

    1. anode
    2. cathode
    3. electrolyte
    4. metal

  2. ______ is used for manufacturing scientific balance.

    1. Steel
    2. Brass
    3. Stainless steel
    4. Magnalium

  3. There are ______ nonmetals in solid state.

    1. 11
    2. 12
    3. 13
    4. 14

  4. Sulphur belongs to ______ group in periodic table.

    1. Boron
    2. Carbon
    3. Oxygen
    4. Halogen

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. Define : Metallurgy.
  6. What is the use of Van Arkel's method ?
  7. Why do nonmetals not react with dilute acids ?
  8. Which crystalline form of sulphur is most stable ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. Describe roasting with two examples.
  10. Mention four uses of hydrogen.
  11. Describe preparation of sulphur from natural gas.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Describe extraction of aluminium by Hall-Heroult method with diagram.
  13. Describe manufacture of ammonia and mention its three uses.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Write a note on chemical reduction method. ORDescribe manufacture of iron using blast furnace.

TEST PAPER 6

UNIT 6 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. The energy released during cellular respiration is stored in ______.

    1. ATP
    2. glucose
    3. NADPH2
    4. lungs

  2. Cockroach shows ______ mode of nutrition.

    1. herbivorous
    2. carnivorous
    3. omnivorous
    4. grazing

  3. ______ is a necessary mineral for clotting of blood.

    1. Calcium
    2. Potassium
    3. Iron
    4. Zinc

  4. Birds excrete wastes in the form of ______.

    1. urea
    2. proteins
    3. uric acid
    4. water

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. What is the aim of nutrition ?
  6. Write the chemical equation for aerobic respiration.
  7. Define : Translocation.
  8. Where are blood antigens located ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. Describe parasitic nutrition.
  10. Describe mechanism of breathing.
  11. Write a note on leucocytes.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Describe nutrition in amoeba with diagram.
  13. Describe human excretory system with diagram.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Describe human respiratory system(diagram not needed). OR Describe : Phloem with diagram.

TEST PAPER 7

UNIT 7 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. ______ is the complimentary system of nervous system.

    1. Circulatory system
    2. Endocrine system
    3. Lymphatic system
    4. Skeletal system

  2. ______ hormone regulates ionic balance.

    1. Vasopressin
    2. Thyroxin
    3. Glucagon
    4. Testosteron

  3. ______ is a very useful method for developing garden.

    1. Cutting
    2. Layering
    3. Grafting
    4. Budding

  4. The normal weight of human child at the time of birth should be ______.

    1. 1.5 kg
    2. 1.5 to 2.5 kg
    3. 3.0 to 3.5 kg
    4. 5.0 to 6.5 kg

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. What is photoperiodism ?
  6. What is meant by autonomous nervous system ?
  7. Give two examples of organisms reproducing by spore formation.
  8. What is vasectomy ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. Mention two characteristics of hormones.
  10. Give two examples of nastic movement.
  11. Mention accessory reproductive glands and their function in human male. OR Mention symptoms of sexually transmitted diseases.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Write in brief about spinal cord.
  13. Describe budding as a method of reproduction.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Describe female reproductive system in humans with diagram.

TEST PAPER 8

UNIT 8 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]



  1. The number of genes in human being is about...

    1. 23
    2. 46
    3. 1,000 to 2,000
    4. 30,000 to 40,000

  2. ______ gave Germplasm theory.

    1. Lamarck
    2. Weismann
    3. Darwin
    4. Hugo De Vries

  3. Biological oxygen demand of ______ is the least.

    1. sewage
    2. sea water
    3. pure water
    4. polluted water

  4. ______ is the first step of sewage treatment.

    1. Precipitation
    2. Chlorination
    3. Sedimentation
    4. Aeration

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]


  5. Define : Heredity.
  6. Mutation is one of the reasons of variation. True or false ?
  7. Mention the major reason for environmental problems.
  8. What is biomagnification ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]


  9. Explain : Analogous organs giving example. OR Mention components of nucleotides.
  10. Explain : Acid rain.
  11. Describe oxidation pond method.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]


  12. Explain Mendel's concept of heredity.
  13. Describe harmful effects of water pollution. OR Describe the interrelationship among population, environment and development.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]


  14. Describe Watson-Crick model for the structure of DNA with diagram.

TEST PAPER 9

UNITS 1,2,3 - 50 MARKS

There are 27 questions in all and time limit is 90 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark
each, Total marks 7]


  1. "There is plenty of room at the bottom." This was stated by...

    1. Issac Newton
    2. Albert Einstein
    3. Richard Feynman
    4. Eric Drexler

  2. The mirror formula is ______.

    1. (1/u)-(1/v) = (1/f)
    2. (1/f)+(1/u) = (1/v)
    3. f = uv/(u+v)
    4. f = (u+v)/uv

  3. In a transparent medium, the velocity of ______ light is the least.

    1. red
    2. green
    3. yellow
    4. violet

  4. 1 unit of domestic electric energy is equal to...

    1. 1 joule
    2. 1 watt-second
    3. 3.6 x 106 j
    4. 3.6 x 106 kwh

  5. The current passing through two separate lines(circuits) of our houses is ______ A and ______ A.

    1. 5,10
    2. 5,15
    3. 10,15
    4. 2,5

  6. During the refining of petroleum, the fraction having highest boiling temperature...

    1. condenses first
    2. condenses last
    3. does not condense
    4. remains in gaseous form

  7. ______ is the largest planet of our solar system.

    1. Earth
    2. Jupiter
    3. Saturn
    4. Neptune


    SECTION - B : ANSWER IN SHORT : [1 mark each, Total
    marks 8]

  8. What is a bucky tube ?
  9. What is an image ?
  10. Current flows in a wire. Can we call the wire charged ? Why ?
  11. Define : Induced electric current.
  12. Define : Solar constant.
  13. What is the full form of KVIC ?
  14. What are meteors ?
  15. What is the basic concept(belief) of Steady-state theory ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total
    marks 10]

  16. Mention applications of bucky ball and carbon nanotubes.
  17. An object is placed at 30 cm in front of a convex lens of focal length 20 cm. Find the position of its image. OR Draw the ray diagram to show working of a compound microscope.
  18. What is electrolysis ? Write Faraday's laws of electrolysis. OR Mention disadvantages of using direct current(DC).
  19. Mention two categories of solar appliances with examples.
  20. Mention the names and the characteristics of terrestrial planets.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each,
    Total marks 15]

  21. Mention the role of nanotechnology in security.
  22. Describe with the help of a diagram how the seven colours of light can be combined to get white light.
  23. Explain : Electric potential and electric potential difference.
  24. Explain : Solar water heater with diagram. OR Describe construction and working of a biogas plant(no diagram).
  25. Write a note on Nakshatras. OR Mention six uses of artificial satellites.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total
    marks 10]

  26. Derive the generalised form of Snell's law.
  27. Derive the expression for equivalent resistance(R) when three resistors R1,R2 and R3 are connected in parallel and find the current flowing through a circuit containing three resistors of 10 Ω, 5 Ω, and 5 Ω connected in parallel with potential difference 4 V. OR Describe the principle and working of an electric generator with diagram.

TEST PAPER 10

UNITS 4,5 - 50 MARKS

There are 26 questions in all and time limit is 90 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 7]


  1. In pH scale, the base of the logarithm of molar concentration of H3O+ ion is ______.

    1. 10
    2. 20
    3. 50
    4. 100

  2. What is used as an antacid ?

    1. Na2CO3
    2. NaHCO3
    3. NaCl
    4. NaOH

  3. ______ is an ore of calcium.

    1. Magnetite
    2. Siderite
    3. Malachite
    4. Gypsum

  4. ______ is a poor conducting metal for heat.

    1. Copper
    2. Silver
    3. Aluminium
    4. Lead

  5. There are ______ nonmetallic elements.

    1. 20
    2. 22
    3. 24
    4. 25

  6. ______ have fruity smell.

    1. Alcohols
    2. Organic acids
    3. Esters
    4. Ketones

  7. Which of the following is artificial rubber ?

    1. Isoprene
    2. Chloroprene
    3. Neoprene
    4. TEFLON


    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 7]

  8. What is used as catalyst in the preparation of vegetable ghee ?
  9. Give two examples of irreversible reaction.
  10. What is the full form of RCC ?
  11. Write the chemical equation for the preparation of quick lime.
  12. Why are metals like sodium, pottasium and aluminium not available in free state in nature ?
  13. Why is ammonia not collected by downward displacement of water ?
  14. Write the chemical equation for the combustion of ethanol.

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 12]

  15. Mention the criteria for chemical equilibrium.
  16. Describe the preparation of bleaching powder giving chemical reaction. OR Mention four uses of washing soda.
  17. Give chemical equations : (i) when iron reacts with steam (ii) when magnesium reacts with hot boiling water. OR Write the chemical equations involved in Bayer's process.
  18. Describe Frasch process to obtain sulphur(no diagram).
  19. Describe : Vulcanisation of rubber.
  20. Describe harmful effects of ethanol.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 9]

  21. Write the chemical formula of ordinary glass and describe its manufacture.
  22. Write three chemical properties of sulphur dioxide.
  23. Describe preparation of methanal from methanol, mention two properties and two uses of methanal. OR Write an introductory note on carbonyl compounds.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 15]

  24. Explain the concept of dynamic nature of chemical equilibrium giving example.
  25. What is concentration of ore ? Describe the process used to concentrate a sulphide ore. OR Describe refining of metals by elecrolysis giving example.
  26. Describe preparation of hydrogen in laboratory with neat diagram.

TEST PAPER 11

UNITS 6,7,8 - 50 MARKS

There are 26 questions in all and time limit is 90 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 7]


  1. In insects the air enters the tracheal system through ______.

    1. spiracles
    2. nostrils
    3. lungs
    4. bronchi

  2. The function of incisors is ______.

    1. cutting
    2. tearing
    3. grinding
    4. chewing

  3. There are ______ types of antigens on erythrocytes.

    1. five
    2. four
    3. three
    4. two

  4. A sunflower plant bends towards the sun; it is ______ response.

    1. thigmonastic
    2. seismonastic
    3. thermonastic
    4. photonastic

  5. ______ is useful where seeds have long dormancy period and poor germination capacity.

    1. Cutting
    2. Layering
    3. Grafting
    4. Regeneration

  6. ______ is an example of retrovirus.

    1. Virus causing AIDS
    2. TMV
    3. Bacteriophage
    4. RIV

  7. Eutrophication increases due to increase in ______.

    1. BOD
    2. industrialisation
    3. DOB
    4. soil erosion


    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 7]

  8. Through what does a frog respire ?
  9. What is lymph ?
  10. Which plant hormones retard growth ?
  11. What is menopause ?
  12. What is the difference between prokaryotic and eukaryotic chromosomes ?
  13. What is meant by organic evolution ?
  14. What is the full form of NEERI ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 12]

  15. Describe the effect of water and carbon dioxide on the process of photosynthesis.
  16. Write a note on blood platelets.
  17. Explain : Photoperiodism OR Mention the names of four endocrine glands in humans.
  18. Distinguish between asexual and sexual reproduction(two points).
  19. Explain : Variation.
  20. Mention two effects of land pollution. OR Draw a chart showing types of environment.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 9]

  21. Describe exchange of gases in roots and stems with diagram. OR Describe digestive system of grass-hopper with diagram.
  22. Write a note on tropism.
  23. Mention any six laws for environmental protection in India.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 15]

  24. Describe excretion in eatrhworm. OR Describe the structure of nephron with diagram.
  25. Describe sexual cycle in human female.
  26. Write a note on types of chromosomes with diagram.

TEST PAPER 12




SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark
each, Total marks 15]


  1. The diameter of a bucky ball is about ______.

    1. 1 A°
    2. 10 A°
    3. 100 A°
    4. 1000 A°

  2. Absolute refractive index of any medium is always ______.

    1. 1
    2. greater than 1
    3. smaller than 1
    4. 0

  3. The unit of electric current is ______.

    1. coulomb-second
    2. coulomb/second
    3. volt/second
    4. coulomb/volt

  4. The direction of magnetic field lines is taken ______.

    1. N to S
    2. S to N
    3. entering both poles
    4. leaving both poles

  5. ______ is the superior quality of coal.

    1. Peat
    2. Lignite
    3. Bituminous
    4. Anthracite

  6. How many satellites does mercury have ?

    1. 30
    2. 21
    3. 8
    4. 0

  7. The concentration of H+ ions in neutral water is ______.

    1. 1 x 10-7 mol/lit
    2. -7.0 mol/lit
    3. 7.0 mol/lit
    4. (1/7) mol/lit

  8. Brine is ______.

    1. Na2CO3
    2. NaHCO3
    3. NaCl
    4. Na2SiO3

  9. The enzyme that converts milk to curd is ______.

    1. lactase
    2. invertase
    3. zymase
    4. cellulase

  10. Brass is an alloy of ______.

    1. copper and nickel
    2. copper and zinc
    3. copper and tin
    4. copper and iron

  11. The atomic number of sulphur is ______.

    1. 15
    2. 16
    3. 17
    4. 18

  12. ______ shows phagocytosis.

    1. Amoeba
    2. Locust
    3. Earthworm
    4. Cockroach

  13. Which multicellular organism lacks the nervous system ?

    1. Hydra
    2. Locust
    3. Sponge
    4. Cockroach

  14. Disease caused by Treponema Palidium is _______.

    1. AIDS
    2. Syphilis
    3. Gonorrhoea
    4. Typhoid

  15. Minamata disease is caused by the pollution of

    1. Mercury
    2. Lead
    3. Arsenic
    4. Cadmium

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total
    marks 15]

  16. What are complimentary colours ?
  17. How many electrons should flow in one second to contribute electric current of 1 ampere ?
  18. What type of magnetic field arises when current passes through a linear wire ?
  19. Define : Solar constant.
  20. Why does the candle get extinguished when air is blown ?
  21. How many meters make 1 light year ?
  22. What is 1 molar(1 M) solution ?
  23. Write the chemical name of plaster of Paris.
  24. What is the monomer of natural rubber ?
  25. What is e.m.f. series (of metals) ?
  26. Give two examples of neutral oxides.
  27. What is the life span of human erythrocytes ?
  28. What is reflex arc ?
  29. What are homologous chromosomes ?
  30. What is Greenhouse effect ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total
    marks 24]

  31. Mention the use of nanotechnology for resources like energy and water.
  32. Explain why dispersion of light occurs.
  33. Three resistors of 5 Ω, 10 Ω and 15 Ω are connected in parallel.If the voltage is 3 V, find the overall current flowing through the circuit. OR Explain the right hand thumb rule for straight conductor.
  34. Write a note on Jupiter.
  35. Describe Arrhenius' concept of acid and base.
  36. Write addition reactions(one each) of formaldehyde and propanone. OR Write a brief note on soap.
  37. Explain calcination giving examples of two reactions.
  38. Explain : Exchange of gases in leaves. OR Describe excretion and osmoregulation in amoeba.
  39. Mention characteristics of hormones.
  40. Write a note on puberty.
  41. Explain homologous organs with example.
  42. Describe Oxidation pond method.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each,
    Total marks 21]

  43. Describe chemical effect of electric current giving example. OR Derive the expression for equivalent resistance(R) of three resistors connected in series.
  44. Explain : Solenoid.
  45. Describe the manufacture of bleaching powder. Write its reaction with dilute sulphuric acid and mention two uses.
  46. Describe froth floatation process with diagram. OR Describe Bayer's process for the concentration of bauxite ore.
  47. Describe light phase of photosynthesis. OR Describe digestive system of grasshopper with diagram.
  48. Describe the role of sex hormones in humans.
  49. Describe Mendel's concept of heredity.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total
    marks 25]

  50. Derive lens formula.
  51. Describe fractional distillation of petroleum with neat diagram and mention the products obtained. OR Describe construction and working of a space shuttle(diagram not necessary).
  52. Explain physical equilibrium with example.
  53. Describe laboratory preparation of hydrogen with diagram.
  54. Describe transportation of mineral elements in plants with diagram. OR Draw a neat diagram of heart and explain its working.

TEST PAPER 13

There are 54 questions in all and time limit is 3 hours.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark
each, Total marks 15]


  1. A bucky ball is a molecule consisting of ______ carbon atoms.

    1. 50
    2. 60
    3. 70
    4. 100

  2. In the spectrum of white light obtained with prism, ______ colour is deviated maximum.

    1. violet
    2. red
    3. green
    4. orange

  3. Which of the following is not correct ?

    1. P = W/t
    2. P = I2R
    3. P = WI
    4. P = VI

  4. The insulation cover on the earth wire is ______ in colour.

    1. red
    2. black
    3. green
    4. white

  5. 1 eV = ______ joule.

    1. 1.6 x 10(-17)
    2. 1.6 x 10(-18)
    3. 1.6 x 10(-19)
    4. 1.6 x 10(-20)

  6. The stars appearing ______ have very high/highest temperature.

    1. red
    2. blue
    3. white
    4. yellow

  7. The acid-base theory by Bronsted and Lowry...

    1. is based on donation of electron.
    2. does not give importance to the solvent.
    3. gives importance to the solvent.
    4. gives operational definition of acid and base.

  8. The formula of soda ash is ______.

    1. NaHCO3
    2. Na2CO3
    3. Na2CO3.10H2O
    4. NaOH

  9. What is the boiling point of acetic acid ?

    1. 98 °C
    2. 108 °C
    3. 118 °C
    4. 128 °C

  10. ______ is the formula of cuprite.

    1. Cu2O
    2. Cu2S
    3. CuCO3
    4. CuCl2

  11. ______ is a neutral oxide.

    1. Na2O
    2. CO2
    3. CO
    4. SO3

  12. The lungs are covered by two membranes called ______.

    1. glottis
    2. epiglottis
    3. pleura
    4. sphincter

  13. ______ pairs of spinal nerves arise from spinal cord.

    1. 21
    2. 31
    3. 23
    4. 46

  14. The method by which the desired characters of two plants can be combined is...

    1. cutting
    2. layering
    3. budding
    4. grafting

  15. The principle of inheritance of acquired characters was given by...

    1. Lamarck
    2. Weismann
    3. Darwin
    4. Hugo De Vries

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total
    marks 15]

  16. Who photographed nanotubes for the first time ?
  17. State Snell's law.
  18. What is overloading ?
  19. What is magma ?
  20. Mention the calorific values of charcoal and wood ?
  21. What is corona ?
  22. State the pH of the solution whose pOH is 3.925.
  23. Why is NaCl added to the Plaster of Paris ?
  24. Write the chemical formulas of butanal and propanone.
  25. What is gangue ?
  26. Why is sulphuric acid known as the King of chemicals ?
  27. What is the function of phloem ?
  28. What is 'scion' ?
  29. Mention the limitation of Darwinism.
  30. What is conservation of environment ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total
    marks 24]

  31. Explain primary and composite colours giving examples. OR Explain why defects of vision arise.
  32. What is electrolysis ? Write Faraday's laws of electrolysis.
  33. Mention two advantages of alternating current.
  34. How are smokeless chulhas more efficient than traditional chulhas ? OR Mention names of terrestrial planets and their characteristics.
  35. Write a note on safety glass.
  36. What are condensation polymers ? Give examples.
  37. Explain with example : Reaction of nonmetals with chlorine.
  38. Describe biosynthetic phase of photosynthesis with diagram. OR Explain : Rhesus factor.
  39. Describe endocrine glands in short.
  40. What individual care should one take to prevent sexually transmitted diseases (STDs) ?
  41. Explain : Variation.
  42. Describe sewage treatment.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each,
    Total marks 21]

  43. Describe tensile strength and thermal conductivity as properties of nanotubes.
  44. Explain Cartesian sign convention for spherical mirrors with the help of a diagram.
  45. Explain the re-use of byproducts obtained during Solvay's ammonia soda process. OR Describe three chemical properties of ethyl alcohol(ethanol).
  46. Write a note on allotropes of sulphur.
  47. Describe nutrition in amoeba with diagram.
  48. Explain : Tropism OR Describe regeneration as a method of reproduction.
  49. Mention harmful effects of water pollution.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total
    marks 25]

  50. Describe construction and working of a simple voltaic cell.
  51. Explain Solar water heater with a neat diagram. OR Describe various orbits of artificial satellites giving appropriate details.
  52. Derive the expression for the equilibrium constant for the reaction : A + B --> C + D .
  53. Describe extraction of aluminium from bauxite using Bayer's process and Hall-Heroult process. OR Explain how metals react with oxygen, water and dilute acids giving proper examples.
  54. Describe excretion in earthworm.

TEST PAPER 14

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE :

[1 mark each, Total marks 15]


  1. The cut-off limit of human eye to see is ______.

    1. 1 nm
    2. 100 nm
    3. 1000 nm
    4. 10000 nm

  2. Magnification for convex mirror is ______.

    1. always positive
    2. always negative
    3. 0
    4. 1

  3. Who had patented more than 1000 inventions during his life time ?

    1. Edison
    2. Volta
    3. Ampere
    4. Faraday

  4. ______ was the first person to notice the magnetic effect of electric current.

    1. Faraday
    2. Ampere
    3. Oersted
    4. Maxwell

  5. Bombardment of neutron on 6Li3 gives ______.

    1. 1H0
    2. 1H1
    3. 2H1
    4. 3H1

  6. The sun stays in one nakshatra for about ______.

    1. 30 days
    2. 13.5 days
    3. 7 days
    4. 1 day

  7. Conversion of milk into curd is ______.

    1. a physical change
    2. a chemical change
    3. not a chemical change
    4. neither a physical nor a chemical change

  8. Helmets are made from ______.

    1. manganese steel
    2. chrome steel
    3. cobalt steel
    4. silicon steel

  9. An organic acid + an alcohol --> ______.

    1. an aldehyde
    2. a ketone
    3. an ester
    4. an amide

  10. Which of the following is the monomer of natural rubber ?

    1. Isoprene
    2. Chloroprene
    3. Neoprene
    4. TEFLON

  11. Liquefaction method is used for the purification of metals with ______.

    1. high melting point
    2. high boiling point
    3. low melting point
    4. low boiling point

  12. Urine mainly consists of ______.

    1. uranium
    2. urea
    3. CO2
    4. sugar

  13. Plant hormones are called ______.

    1. hypohormones
    2. metahormones
    3. phytohormones
    4. cytohormones

  14. Mutation theory was given by ______.

    1. Lamarck
    2. Darwin
    3. Hugo De Vries
    4. Mendel

  15. World Environment Day is celebrated every year on ______.

    1. 5th March
    2. 15th April
    3. 15th May
    4. 5th June

    SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 15]


  17. What is a simple microscope ?
  18. Define : 1-ohm resistance.
  19. What type of magnetic field arises when current passes through a linear wire ?
  20. Where are hot water geysers found in Gujarat ?
  21. What did Ptolemy believe about the Universe ?
  22. Which is the gas mainly present in the atmosphere of Pluto ?
  23. Define : pH.
  24. Write the formula of acetone cyanohydrin.
  25. What is the full form of PABA ?
  26. Where does the biosynthetic phase of photosynthesis take place ?
  27. Mention the types of nephridia in earth worm.
  28. Define : Reproduction.
  29. Where are genes located ?
  30. What does environment mean ?
  31. What is meant by biodegradable pollutants ?

    SECTION - C : ANSWER IN BRIEF : [2 marks each, Total
    marks 24]

  32. Write a brief note on bucky ball.
  33. Distinguish between compound microscope and astronomical telescope[2 points]
  34. A lamp of resistance 20Ω is joined to a battery of 12 V. Find the value of the resistance to be connected in series with the lamp in order to get current of 0.5 A. OR Explain the importance of earthing wire.
  35. Explain : The energy obtained from nuclear fusion is better than that obtained from fission reactions.
  36. Calculate the pH of 0.03 M aqueous solution of NaOH.(Take log10 3 = 0.4771). OR Mention the criteria of chemical equilibrium.
  37. Write a note on saponification.
  38. Mention four uses of hydrogen.
  39. Describe exchange of gases in tissues.
  40. Write four points about erythrocytes.
  41. Explain the importance of ultrapure metals.
  42. Mention the characteristics of hormones.
  43. Explain : Homologous organs OR Draw a chart showing types of environment.

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each,
    Total marks 21]

  44. Describe Ohm's experiment. OR Derive an expression for equivalent resistance(R) when three resistors of R1, R2 and R3 Ω are connected in parallel.
  45. Explain : Solenoid.
  46. Describe preparation of Plaster of Paris, write its two properties and two uses. OR Describe preparation of acetic acid by fermentation as well as by chemical method.
  47. Describe refining of metals by electrochemical method.
  48. Mention organs of human respiratory system and describe mechanism of breathing.
  49. Draw a neat diagram of brain and write about hind brain.
  50. Explain : Grafting with diagram.

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total
    marks 25]

  51. Explain : Total internal reflection and mirage with diagram.
  52. Describe nuclear reactor with diagram. OR Write a note on construction and working of a space shuttle with simple diagram.
  53. With the help of an experiment explain the concept of dynamic nature of chemical equilibrium.
  54. Write a detailed note on ammonia, its manufacture and mention its properties and uses.
  55. Describe the structure of chromosome with diagram. OR Describe Watson-Crick model for the structure of DNA.

ANSWER IN BRIEF



  1. Mention physical properties of nonmetals.
    ANS :

    • Nonmetals occur in all three states : solid, liquid and gas.

    • They are neither malleable nor ductile.

    • They do not conduct heat and electricity (graphite is an exception).

    • They are lustreless.

    • They are generally soft (diamond is an exception).

    • They are brittle.

    • They generally have low melting points and boiling points.

    • They are light in weight.

    • Solid nonmetals do not produce ringing sound.



  2. Explain chemical properties of nonmetals.
    ANS : Nonmetals are electronegative elements because they accept electrons and form negatively charged ions. For example, oxygen forms negative oxide ion O-2 by accepting two electrons.

    1/2 O2 + 2 e- → O-2



    REACTION WITH OXYGEN : Nonmetals form either acidic oxide or neutral oxide with oxygen.

    • When carbon burns in air, it forms carbon dioxide which is an acidic oxide.

      C(s) + O2(g) → CO2(g)



      Carbon dioxide dissolves in water to form carbonic acid [H2CO3].

      CO2(g) + H2O(l) → H2CO3(aq)



    • When sulphur burns in air, it reacts with oxygen to form sulphur dioxide which is an acidic oxide.

      S(s) + O2(g) → SO2(g)



      Sulphur dioxide dissolves in water to form sulphurous acid [H2SO3]

      SO2(g) + H2O(l) → H2SO3(aq)



    • Phosphorus forms phosphurus pentoxide (2P2O5) with oxygen which dissolves in water to form phosphoric acid [H3PO4(aq)].

      P4(s) + 5O2(g) → 2P2O5(g)

      2P2O5(g) + 6H2O → 4H3PO4(aq)


    • Oxides like CO, N2O, H2O are neutral oxides as their aqueous solutions are neither acidic nor basic or they do not have any effect on any litmus paper.



    REACTION WITH ACIDS : Nonmetals do not react with dilute acids as they are not able to displace hydrogen from acids.

    REACTION WITH CHLORINE : Nonmetals form chlorides with chlorine. These chlorides are either liquid or gas.



    REACTION WITH HYDROGEN : Nonmetals form covalent hydrides with hydrogen.



    Methane (CH4), hydrochloric acid (HCl), etc. are hydrides of nonmetals.

  3. Describe the Importance of nonmetals.
    ANS :

    • Carbon is the main constituent of all nutrients needed for the growth and development of living organisms.

    • Carbon is also used in the preparation of gunpowder, sugar, cold drinks, dry ice, urea, etc.

    • Oxygen supports life on earth.

    • Oxygen also supports combustion process.

    • Nitrogen is the major constituent of the atmosphere.

    • Nitrogen reduces the rate of combustion.

    • Nitrogen is used in the preparation of nitric acid, nitroglycerin and fertilisers.

    • Hair, onion, garlic, etc. contain sulphur.

    • Sulphur is used in the preparation of paper pulp, fungicides, etc.

    • Phosphorus is used in making matchsticks, insecticides, etc.



  4. Write a few sentences on Hydrogen.
    ANS :

    • Hydrogen was discovered in 1766 AD by English chemist Cavendish.

    • Its chemical symbol is H.

    • It is the lightest of all elements.

    • It is the first element of the periodic table.

    • Hydrogen does not occur in free state in the atmosphere.

    • It is a diatomic molecule.

    • it is a colourless, odourless gas.

    • It is present in outer space.

    • It is the main element present in sun.

    • Sun's energy is produced due to the conversion of hydrogen into helium.

    • Hydrogen is manufactured on large scale from natural gas by Steam Reforming.



  5. Describe preparation of hydrogen in laboratory.
    ANS :


    AIM : To prepare hydrogen gas in laboratory.

    APPARATUS & MATERIAL : Conical flask, Thistle funnel, glass container, bee-hive shelf, glass jar, glass tube, zinc granules, hydrochloric acid, water, etc.

    PROCEDURE :

    • Zinc granules are taken in conical flask and the equipment is set up as shown in figure.

    • Dilute hydrochloric acid is added slowly to the flask through thistle funnel.



    OBSERVATION : The reaction between zinc granules and dilute hydrochloric acid produces hydrogen gas which is collected by downward displacement of water in an inverted jar.

    CHEMICAL REACTION :

    Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

    NOTE : In place of dilute HCl we can also use dilute H2SO4.

    Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g)

  6. Describe manufacture of hydrogen from natural gas.
    ANS :

    • Hydrogen gas is manufactured on large scale from natural gas by steam reforming process.

    • Methane (the main constituent of natural gas) is mixed with steam and passed over nickel catalyst at 800°C and 30 atm pressure.

    • The reaction produces carbon dioxide and hydrogen.


    • Hydrogen gas can also be obtained by the electrolysis of acidified water.



  7. Describe chemical properties of hydrogen.
    ANS :

    1. Hydrogen gas burns in air (oxygen) with a blue flame forming watervapour.

      2H2(g) + O2(g) → 2H2O(g)


    2. It burns in chlorine to form white fumes of hydrogen chloride gas.

      H2(g) + Cl2(g) → 2HCl(g)

      Similarly it forms hydrogen fluoride gas with fluorine.

      H2(g) + F2(g) → 2HF(g)


    3. It forms hydrides with metals like lithium, sodium and calcium.

      H2(g) + 2Li(s) → 2LiH(s)

      H2(g) + 2Na(s) → 2NaH(s)

      H2(g) + Ca(s) → CaH2(s)


    4. Hydrogen reduces oxides of those metals, which are less reactive, to free metals. Thus, when hydrogen is passed over hot copper oxide copper metal and water are produced.

      CuO(s) + H2(g) → Cu(s) + H2O(l)



  8. Write a detailed note on ammonia, its manufacture, properties and uses.
    ANS :
    AMMONIA : Ammonia is a very important industrial chemical as it is used for the manufacture of a wide range of chemicals. It is manufactured commercially by Haber's process.

    MANUFACTURE : A mixture of nitrogen and hydrogen in the ratio of 1 : 3 is heated under 200 - 300 atm pressure in presence of catalyst (finely divided iron + molybdenum) at about 450 °C. The reaction is reversible.



    PHYSICAL PROPERTIES :

    • It is a colourless gas.
    • It has characteristic pungent smell.
    • It is poisonous.
    • It is lighter than air.
    • It is highly soluble in water.
    • It can be liquefied easily at room temperature by applying about 9 atm pressure.
    • Liquid ammonia boils at 239.7 K and freezes at 198.4 K.
    • Liquid ammonia has very high heat of vaporization.
    • In liquid state, the ammonia molecules are present as associated molecules.


    CHEMICAL PROPERTIES :

    • Ammonia reacts with hydrochloric acid to form ammonium chloride.

      NH3(g) + HCl(l) → NH4Cl(s)

    • Ammonia decomposes in presence of electric discharge.



    • Ammonia reacts with oxygen in presence of catalyst platinum at 1073 K to form nitric oxide.



    • Ammonia reacts with carbon dioxide to form urea (NH2CONH2)
    • Aqueous solution of ammonia acts as a base.


    USES :

    • In the manufacture of fertilisers such as urea, ammonium nitrate and ammonium sulphate.
    • In the manufacture of nitric acid by Ostwald process.
    • In the manufacture of baking soda and washing soda.
    • In the manufacture of some medicines such as para-aminobenzoic acid (PABA), folic acid, etc.
    • As a nonaqueous solvent.
    • As a coolant in ice factories and in refrigerators.


  9. Describe Extraction of Sulphur.
    ANS : Pure sulphur is obtained by (i)Frasch Process or (ii) from natural gas and oil by chemical process.

    FRASCH PROCESS : The process is used to obtain pure sulphur from the sulphur bed in the ground. It is based on the fact that sulphur has relatively low melting point (388 K).


    • A hole of about 30 cm diameter is bored upto the sulphur bed.
    • Three concentric pipes A, B and C of different diameters are descended upto sulphur deposits as shown in the figure.
    • Pressurised superheated water at about 170°C is forced down through the outermost pipe A. The heat of water melts the underground sulphur.
    • Hot compressed air is passed through the innermost pipe C.
    • A mixture of molten sulphur and water comes out through central pipe B.
    • The sulphur-water emulsion is allowed to settle in settling tanks. Yellow solid sulphur separates from water after cooling. This sulphur is 99.5% pure.


    FROM NATURAL GAS AND OIL :

    • Sulphur compounds in natural gas and oil are first converted into hydrogen sulphide. (H2S).
    • Hydrogen sulphide is heated in presence of oxygen to obtain sulphur dioxide.
    • This sulphur dioxide is then heated with additional hydrogen sulphide in the presence of catalyst Fe2O3 to obtain sulphur in free state.




  10. Write a note on Allotropes of sulphur.
    ANS :

    • Different arrangement of molecules in the crystals give rise to allotropes of sulphur.
    • There are two allotropes of crystalline sulphur. (i)Rhombic sulphur and (ii) Monoclinic sulphur.
    • Rhombic sulphur is stable below 96°C and its crystals have octahedral shape.
    • Monoclinic sulphur is stable above 96°C and its crystals are needle-shaped.
    • As one allotrope changes into another at 96°C, it is called TRANSITION TEMPERATURE for sulphur.
    • Both allotropes have similar chemical properties but their physical properties differ due to their different physical structures.
    • When solid sulphur is heated its molecular chain breaks which on further heating yields viscous liquid sulphur. This on heating starts boiling.


  11. Mention Chemical properties of sulphur.
    ANS :

    • Sulphur burns with blue flame and produces sulphur dioxide.

      S(s) + O2(g) → SO2(g)



    • REACTION WITH ACIDS : Sulphur is oxidised to sulphur dioxide when it reacts with hot and concentrated sulphuric acid.

      S(s) + 2 H2SO4(aq) → 2H2O(l) 3SO2(g)



      Sulphur is oxidised to sulphuric acid when it reacts with hot and concentrated nitric acid.

      S(s) + 6HNO3(aq) → H2SO4(aq) + 6NO2(g) + 2H2O(g)



    • REACTION WITH CARBON : Sulphur reacts with carbon at high temperature to give carbon disulphide.

      C(s) + 2S(s) → CS2(l)



    • REACTION WITH HYDROGEN : When hydrogen gas is passed through boiling sulphur, foul smelling hydrogen sulphide gas is formed.

      S(s) + H2(g) → H2S(g)




  12. Mention uses of sulphur.
    ANS :

    • In the manufacture of sulphuric acid.
    • As an antiseptic in skin ointments.
    • For skin treatment in beauty parlours.
    • For making dyes, matches, gunpowder, pulp of paper and fireworks.
    • In vulcanisation of rubber.
    • For manufacturing carbon disulphide which is a solvent.
    • As a disinfectant, fungicide, germicide, etc. for destroying bacteria, fungi, insects, etc.
    • In printing of clothes.


  13. Write a detailed note on sulphur dioxide.
    ANS : The reaction of sulphur with oxygen gives sulphur dioxide.

    S(s) + O2(g) → SO2(g)



    PHYSICAL PROPERTIES :

    • It is a colourless gas.
    • It has a pungent smell.
    • It is a pollutant gas.


    CHEMICAL PROPERTIES :

    • Sulphur dioxide dissolves in water to form sulphurous acid (H2SO3).

      SO2(g) + H2O(l) ↔ H2SO3(aq)



    • Sulphur dioxide reacts with aqueous sodium hydroxide to form sodium sulphite (Na2SO3).

      SO2(g) + 2NaOH(aq) → Na2SO3(aq) + H2O(l)



    • When sulphur dioxide gas is passed through lime-water, the solution turns cloudy due to the formation of insoluble calcium sulphite (CaSO3).

      SO2(g) + Ca(OH)2(aq) → CaSO3(s) + H2O(l)



    • When sulphur dioxide gas is passed through an aqueous solution of hydrogen sulphide, it turns milky (turbid) due to formation of colloidal sulphur.

      SO2(g) + 2H2S(aq) → 3S(s) + 2H2O(l)



    • Sulphur dioxide combines with oxygen in presence of catalyst vanadium pentoxide [V2O5] at 450°C to form sulphur trioxide.




    USES :

    • For the manufacture of sulphuric acid.
    • As a preservative in orange and lemon squashes and jams.
    • For bleaching of wood pulp in paper industry.
    • As a disinfectant.


  14. Describe manufacture of sulphuric acid by Contact Process.
    ANS : The contact process is divided into different stages and uses various units such as sulphur burner, precipitator, steam scrubber, drying tower, arsenic purifier, contact chamber and absorption unit.

    PREPARATION OF SO2 : SO2 is obtained by burning sulphur or pyrites.



    PURIFICATION OF SO2 :

    • The sulphur dioxide obtained during above process contains impurities like sulphur dust, acid fog, moisture, As2O3, etc.
    • All these impurities are removed one by one by passing the gases through precipitator (to remove dust particles), steam scrubber (to remove acid fog), dry tower (to remove moisture) and arsenic purifier (to remove arsenious oxide).


    CONVERSION OF SO2 into SO3 IN CONTACT CHAMBER : The mixture of purified SO2 and air is passed over catalyst vanadium pentoxide [V2O5] or platinum in contact chamber to produce SO3.



    ABSORPTION OF SO3 IN CONC. H2SO4 : SO3 obtained from the contact chamber is dissolved in 98% H2SO4 acid in absorption tower giving oleum, H2S2O7. [Oleum is also known as 'fuming sulphuric acid' or 'pyrosulphuric acid.]



    The dissolution of SO3 in water produces a large amount of heat resulting in the formation of dense fog. This fog does not condense easily. On the other hand, SO3 dissolves in 98% sulphuric acid without complication.

    Sulphuric acid of any concentration can be obtained by diluting oleum with water.

    H2S2O7(l) + H2O(l) → 2H2SO4(aq)



    Contact process yields sulphuric acid which is pure and of about 100% strength.

  15. Write physical properties and uses of sulphuric acid.
    ANS :

    PHYSICAL PROPERTIES :


    • There are two forms of sulphuric acid : (i)concentrated sulphuric acid (ii) dilute sulphuric acid.
    • Concentrated sulphuric acid contains about 98% sulphuric acid and 2% water.
    • Concentrated sulphuric acid is a colourless, viscous, heavy liquid.
    • It has high boiling point.
    • It has high affinity for water.
    • Dilute sulphuric acid contains about 10% sulphuric acid and 90% water.
    • Dilution of concentrated sulphuric acid by addition of water is a highly exothermic reaction.


    USES :

    • In the manufacture of fertilisers, ammonium sulphate and calcium super phosphate (superphosphate of lime).
    • In the manufacture of paints, dyes and pigments.
    • In the manufacture of soap and detergent.
    • In lead storage battery.
    • In paper and textile industry.
    • In the manufacture of alums, drugs, insecticides, etc.
    • In the manufacture of hydrochloric acid and nitric acid.


  16. Write chemical properties of sulphuric acid.
    ANS :

    • Concentrated sulphuric acid dehydrates sugar to carbon. The black mass of carbon is called sugar charcoal and the reaction is called charring of sugar.



    • Dilute sulphuric acid reacts with metals like zinc and iron to form metal sulphates and hydrogen gas.

      Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g)

      Fe(s) + H2SO4(aq) → FeSO4(aq) + H2(g)

    • Sulphuric acid is strong dibasic acid from which two hydrogen atoms can be displaced in solution.

      H2SO4(l) + 2H2O(l) → 2H3O+(aq) + SO4(aq)-2

ANSWER IN BRIEF

  1. Explain : Functional group.
    ANS:

    • An atom or a group of atoms responsible for the chemical reactions of an organic compound is known as 'Functional Group'.
    • Functional groups are responsible for the properties of an organic compound.
    • Functional group is a characteristic of an organic compound.
    • Examples :

      1. Alcohol (-OH)
      2. Aldehyde (-CHO)
      3. Ketone (>C=O)
      4. Organic acid (-COOH)
      5. Ester (-COOR, R is alkyl part)

    • Thus, CH3CH2OH (ethanol) is an alcohol and -OH group decides its properties.
    • All compounds having similar functional group have similar properties.


  2. Write physical properties of ethyl alcohol.
    ANS:

    • Pure ethanol is colourless.
    • Its boiling point is 78°C.
    • It is miscible with water.
    • It is neutral.


  3. Mention uses of ethyl alcohol.
    ANS:

    • As an antiseptic to clean wounds.
    • To sterilise syringes, gauze, etc.
    • In alcoholic drinks.
    • In preparation of rectified spirit (alcohol containing 5% water).
    • As an antifreezing agent in the radiators of vehicles in cold countries as the mixture of water with alcohol lowers the freezing point of water.


  4. Write about the harmful effects of ethyl alcohol.
    ANS:

    • Person consuming alcohol becomes addict to it.
    • Eyesight weakens and the person may lose eyesight in the long run.
    • Ethyl alcohol damages liver and may cause death of the person.
    • To restrict consumption of ethyl alcohol, some poisonous substance like methanol or CuSO4 is added to ethanol. This is called 'Denatured Ethyl Alcohol'.


  5. Show that the H atom in the -COOH group has acidic nature.
    ANS:The H atom in the -COOH group has acidic nature. The following two reactions are the proof of this.

    When acetic acid reacts with a metal like sodium or potassium, hydrogen gas is evolved.



    Acetic acid reacts with an alkali to form the respective salt of acetic acid and water.



  6. What is an enzyme ? Write three reactions involving different enzymes.
    ANS: An enzyme is a biochemical catalyst which breaks down complex organic molecules into simpler ones. Some reactions involving enzymes are :





    [NOTE : There is no mention in the text book (GSEB) of what an enzyme is.]

  7. Mention the difference between 'Denatured Alcohol' and 'Rectified Spirit'.
    ANS:

    • Ethyl alcohol containing 5% water is called 'rectified spirit'.
    • Ethyl alcohol containing some poisonous substance like methanol or copper sulphate in small amount is called 'denatured alcohol'.
    • The purpose of adding poisonous substance is to prevent people from consuming alcohol as its addiction is harmful in the long run.


  8. Write the names of the products of oxidation reaction of ethanol in presence of KMnO4 and chromium oxide.
    ANS: Oxidation of ethanol in presence of KMnO4 yields ethanoic acid and water whereas its oxidation in presence of chromium oxide yields ethanal and water.

  9. Explain : Tollen's test.
    ANS:
    [NOTE : Though this question appears in the list of questions given at the end of the chapter in the text book (GSEB), the description regarding it is given under the title 'ONLY FOR INFORMATION'. Refer to 'Activity 4' in the text book.]

    • Add sufficient NaOH to a solution of silver nitrate to obtain permanent precipitates.
    • Dissolve the precipitates in NH4OH to prepare Tollen's reagent.
    • Add some aldehyde in the test tube containing Tollen's reagent and place it in a beaker containing water.
    • Heat the water in the beaker.
    • The aldehyde will be oxidised and silver (Ag) metal will be liberated. This silver will appear as a mirror on the inner wall of the test tube.


  10. Write addition reactions of formaldehyde and propanone.
    ANS: Formaldehyde and propanone show following addition reactions with HCN forming corresponding cyanohydrins.





  11. What is a polymer ? Give its classification.
    ANS: A polymer is a long-chain compound with many smaller units called monomers.

    Based on their reactions, polymers are classified into (i) Addition polymer and (ii) Condensation polymer.

  12. Mention the types of artificial polymers giving examples.
    ANS: Following are the types of artificial polymers :

    1. Synthetic fibre : rayon, nylon, polyester.
    2. Plastic : polythene, PVC, bakelite, melamine.
    3. Synthetic Rubber : butadiene, neoprene.


  13. What is the difference between 'thermoplastic' and 'thermosetting plastic' ?
    ANS:

    • Polymers which become soft on heating and regain original shape on cooling are called 'thermoplastics'. for example : polythene, polyvinyl chloride (PVC), and polystyrene.
    • Polymers which do not soften on heating at high temperature are called 'thermosetting plastics'. If at all they soften then they do not regain their shape. for example : bakelite, melamine.


  14. What are addition polymers ? Give examples.
    ANS: Addition polymers are formed by addition of one or more than one (same or different) unsaturated monomer having double or triple bond.

    Polythene, PVC, TEFLON, polypropene, natural rubber, polubutadiene and neoprene are addition polymers.

  15. What are condensation polymers ? Give examples.
    ANS: A polymer formed by the condensation of two or more than two monomers with the elimination of a simple molecule like water or ammonia is called a condensation polymer.

    Polyester, polyamides and phenol-formaldehyde are condensation polymers.

  16. Write a brief note on soap.
    ANS: Soaps are sodium or potassium salts of higher fatty acids like stearic or palmitic acid, etc. In soaps, -COONa is the functional group attached to the hydrocarbon part.

    PREPARATION : On heating vegetable oil or animal fat (esters of higher fatty acids) with sodium hydroxide, sodium salt of fatty acid (soap) and glycerol are formed.



    This process is known as Saponification.

  17. Write a note on 'Production of Soap'.
    ANS:
    [NOTE : this is described as preparation of soap as Activity 5 in the text book (GSEB) under the title 'For information of students'. The process described there is actually laboratory preparation of soap and is far from (large scale) production of soap.
    However, since the question appears in the list of questions given at the end of the chapter, we write the following answer.].

    • Take 20 ml of vegetable oil in a beaker and add 20% aqueous solution of NaOH to it.
    • Heat the mixture and shake it constantly till the mixture becomes dense.
    • Add 5 to 10 g NaCl to it.
    • On cooling the mixture, insoluble soap comes to the upper part of the beaker.
    • It is taken out in a separate plate and allowed to dry.
    • We can add fragrant materials, antiseptic drugs, fillers or any other additive as per the requirement.
    • Soap is generally used in the form of a cake in daily life.

      [NOTE : While preparing the text book, the so-called experts have forgotten to realise that by taking 20 ml vegetable oil it is difficult to prepare even single cake of soap. I am referring to the sentence given on page 217 which reads : 'Take this in other vessel and prepare cakes'.]


  18. Write a note on Detergents.
    ANS:

    • Detergents are sodium salts of long-chain sulphonates.
    • In detergents, -SO3Na is the functional group attached to hydrocarbon part.
    • Detergents are superior to soaps as soaps cannot be used with hard water. Soaps form insoluble salts of calcium and magnesium in hard water and cleansing becomes difficult.


  19. Distinguish between soap and detergent.
    ANS:




........................................................................................................





  1. Explain with example : Reaction of nonmetals with chlorine.
    ANS: Nonmetals form chlorides with chlorine. These chlorides are either liquid or gas.



  2. Explain with example : Reaction of nonmetals with hydrogen.
    ANS: Nonmetals form covalent hydrides with hydrogen.



    Methane (CH4), hydrochloric acid (HCl), etc. are hydrides of nonmetals.

  3. Mention physical properties of hydrogen.
    ANS:

    • Hydrogen is the lightest gas.

    • It is twenty times lighter than air.

    • It is a colourless and odourless gas.

    • It is insoluble in water.

    • It is inflammable

    • It is nonpoisonous.



  4. Mention uses of hydrogen.
    ANS:

    • Hydrogen Welding : When an electric arc is passed through hydrogen, it splits into atoms which release large amount of heat when they recombine to form molecules. This heat is used to melt and join (weld) the metals.

    • In the manufacture of ammonia by Haber's process.

    • In the manufacture of methanol and hydrochloric acid.

    • Liquid hydrogen is used as a fuel in space shuttles.

    • In the manufacture of vegetable ghee.



  5. Mention physical properties of sulphur.
    ANS:

    • It is pale greenish-yellow or greyish-yellow powder.
    • It is odourless and tasteless.
    • It is insoluble in water.
    • It is soluble in organic solvents like carbon disulphide, toluene (methyl
      benzene), etc.
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