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30) Which one of the following has the highest heat of neutralisation?
a) Strong acid + strong base.
b) Weak acid + weak base.
c) Strong acid + weak base.
d) Weak acid + strong base.
ANSWER : Strong acid + strong base.
31) In the following thermochemical equation at 273 K value of ?n is 2 C6H6
+ 15O2 -> 12 CO2 + 6H2O.
a) +3.
b) – 1.5.
c) +1.5.
d) – 3.
ANSWER : – 3.
32) The enthalpy of formation of compounds A, B, C and D are – 84.00,
+24.00, +6.00 and – 16.00 kcal per mole respectively. The correct order of
increasing stability of the compound is:
a) A<B<C<D
b) D<C<A<B
c) B<C<D<A
d) C<D<B<A
ANSWER : B<C<D<A
33) Vibrational energy is possessed by molecule containing:
a) one atom.
b) two atoms.
c) does not depend upon the number of atoms.
d) none of these.
ANSWER - two atoms.
34) 11 kg of a gas expands isothermally and reversibly. The amount of work
done is minimum if the gas is:
a) NO2.
b) CH4.
c) Cl2.
d) O2
ANSWER - Cl2
35) The difference between heats of reaction at constant pressure and at
constant volume for the reaction at 27°C in kJ is 2 C6H6 +
15O2 ? 12 CO2 + 6H2O.
a) 3.72.
b) -3.72.
c) +7.48.
d) – 7.48
ANSWER : – 7.48
36) Relation between the following equation is
C (diamond) + 2H2 -> CH4 ; ΔH1
C (g) + 4H -> CH4 ; ΔH2
a) ΔH1 > ΔH2
b) ΔH1 < ΔH2
c) ΔH1 = ΔH2
d) ΔH1 = ½ x ΔH2
ANSWER : ΔH1 > ΔH2
37) ΔH will be more than ΔE in:
a) 2 NO2 -> N2O4
b) 4NO2 + O2 -> 2 N2O5
c) H2 + I2 -> 2 HI
d) C + ½ O2 -> CO.
ANSWER : C + ½ O2 -> CO.
38) The enthalpy of diamond is not zero because:
a) it is more stable than graphite.
b) it is less stable than graphite.
c) it is equally stable to graphite.
d) all of these.
ANSWER : it is less stable than graphite.
39) The values for enthalpy of combustion is H2, CH4,
C2H6 and graphite are -285.8, -890, -1560 and 393.5 kJ
respectively. The standard enthalpy of formation ofC3H8 is
-103.8 kJ/ mol. The enthalpy of reaction is C3H8 + H2 -
-> C2H6 + CH4.
a) -55.7 kJ / mol.
b) -557 kJ / mol.
c) – 45.7 kJ / mol.
d) 55.7 kJ / mol.
ANSWER : -55.7 kJ / mol.
40) Exothermic change is observed in:
a) evaporation of liquid.
b) fusion of solid.
c) condensation of liquid.
d) none of these.
ANSWER : condensation of liquid.
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