87. Atmospheric air contains the following in varying amounts. Arrange these in decreasing order:
    1) Nitrogen
    2) Carbondioxide
    3) Argon
    4) Oxygen
    (a) 4,1,2,3
    (b) 1,3,2,4
    (c) 3,1,2,4
    (d) 1,4,3,2
Ans: (d)
88. Consider the following elements: [NDA2004]
    1) Copper
    2) Gold
    3) Platinum
    4) Silver
    Which of the above elements exist free in nature?
    (a)  1 and 2
    (b)  2 and 3
    (c)  1, 2 and 4
    (d)  3 and 4
Ans: (b)
89. Match the following: [IAS 1999]
    Drugs/Chemicals         Their uses
    A. Atropine             1. Local anaesthesia
    B. Ether                2. Heart trouble
    C. Nitroglycerine       3. Dilation of pupil
    D. Pyrethrin            4. Mosquito control
         A         B        C          D
    (a)  1         3        2          4
    (b)  1         3        4          2
    (c)  3         1        4          2
    (d)  3         1        2          4
Ans: (d)
90. Match the following
    A. Silver bromide       1. Etching of glass
    B. Hydrogen peroxide 2. Purification of air
    C. Ozone                3. Bleaching agent
    D. Hydrofluoric acid    4. Photography
         A         B        C          D
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