Ans: (b)
31. Alum is used
    (a) as an analgesic
    (b) in the purification of water
    (c) as a fertilizer
    (d) as a disinfectant
Ans: (b)
32. Lunar caustic is
    (a) calcium sulphate
    (b) ammonium chloride
    (c) caustic soda
    (d) silver nitrate
Ans: (d)
33. The formula for cane sugar is
    (a) C6H12O6
    (b) C2H5OH
    (c) C12H22O11
    (d) C7H8O
Ans: (c)
34. Which of the following is not a chemical change?
    (a) Burning of magnesium ribbon in air
    (b) Distillation of water
    (c) Heating of cane sugar
    (d) Setting of cement
Ans: (b)
35. The process that takes place in the atom bomb is
    (a) nuclear" fusion
    (b) radioactive disintegration
    (c) nuclear fission
    (d) chemical decomposition
Ans: (c)
36. Which of the following is not a metal?
    (a) Lithium
    (b) Helium
    (c) Sodium
    (d) Cobalt
Ans: (b)
37. Match the following:
    List-I                            List-2
    (Element)                         (Nature)
    A. Gold                           1. liquid metal
    B. Mercury                        2. solid non-metal
    C. Bromine                        3. solid metal
    D. Sulphur                        4. liquid non-metal
    Codes:
         A          B         C       D
    (a) 3           2         1       4
    (b) 3           1         4       2
    (c) 2           3         1       4
    (d) 2           4         1       3
Ans: (b)
38. Which of the following is not a chemical change?
    (a) Rusting of iron
    (b) Burning of magnesium
    (c) Sublimation of iodine
    (d) Electrolysis of water
Ans: (c)
39. Which of the following is not a physical change?
    (a) Distillation of water
    (b) Action of heat on potassium chlorate
    (c) Powdering of glass
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