B. Big Bang Theory                 2. W. Heisenberg
    C. Quantum Theory of Matter        3. Bohr and Wheeler
    D. Wave Theory of Light            4. Huygens
         A         B          C        D
    (a)  1         2          3        4
    (b)  4         3          2        1
    (c)  3         1          2        4
    (d)  3         2          1        4
Ans: (a)
78. The most electronegative element among the following is : [NDA 2003]
    (a) fluorine
    (b) oxygen
    (c) sodium
    (d) sulphur
Ans: (a)
79. The essential element in all organic compounds is :
    (a) nitrogen
    (b) sulphur
    (c) carbon
    (d) chlorine
Ans: (c)
80. Match the columns:
    Type of Mixture                    Method of Separation
    A. Insoluble solid and liquid      1. Distillation
    B. Two immiscible liquids          2. Evaporation
    C. Soluble solid and liquid        3. Use of Separating funnel
    D. Completely miscible liquids     4. Decantation
         A         B          C        D
    (a)  1         2          3        4
    (b)  2         3          4        1
    (c)  3         1          2        4
    (d)  4         3          2        1
Ans: (d)
81. Match the following: [IAS 2004]
    Fuel Gases                Major Constituents
    A. CNG                    1. Carbon monoxide, Hydrogen
    B. Coal Gas               2. Butane, Propane
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