(d) ammonium persulphate
Ans: (b)
56. Match the following: [NDA 1993]
    Process                 Changes
    A. Evaporation          1. Liquid into gas
    B. Sublimation          2. Gas into liquid
    C. Freezing             3. Solid into gas
    D. Melting              4. Solid into liquid
                            5. Liquid into solid
         A         B        C          D
    (a)  1         2        4          3
    (b)  3         1        2          4
    (c)  2         1        4          3
    (d)  2         1        3          4
Ans: (d)
57. Which of the following causes the rusting of iron? [NDA 1995]
         1) Oxidation
         2) Reduction
         3) Chemical reaction with oxygen
         4) Chemical reaction with CO2
    (a) 1 and 2
    (b) 2 and 3
    (c) 3 and 4
    (d) 1 and 3
Ans: (c)
58. Which of the following statements is/are true? [NDA 1994]
         1) The process of oxidation leads to a gain of electrons.
         2) The process of oxidation leads to a loss of electrons.
         3) The process of reduction leads to a gain of electrons.
         4) The process of reduction leads to a loss of electrons.
    (a) 1 only
    (b) 1 and 4
    (c) 2 and 3
    (d) 4 only
Ans: (c)
59. Match the following: [IFS 1989]
    Process                 Materials obtained
    A. Hydrogenation        1. Vanaspati
    B. Evaporation          2. Ethyl alcohol
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