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NEET Chemistry : Thermodynamics

Multiple Choice Questions

11.

Which of the following are not state functions?
I) q + W
II) q
III) W
IV) H-TS

(I) and (IV)
(II) (III) and (IV)
(I), (II) and (III)
(I), (II) and (III)

12.

The values of ΔH and ΔS for the reaction, C_(graphite) + CO₂(g) → 2 CO (g) are 170 kJ and 170 JK^-1 respectively. This reaction will be spontaneous at

710 K
910 K
1110 K
1110 K

13.

Enthalpy change for the reaction,

4H (g) → 2H₂ (g) is - 869.6 kJ

The dissociation energy of H - H bond is

-869.6 kJ
+434.8 kJ
+217.4 kJ
+217.4 kJ

14.

Standard entropies X₂, Y₂ and XY₂ are 60, 40 and 50 J K^-1 mol^-1 respectively for the reaction

$1 half space straight X subscript 2 space plus 3 over 2 space straight Y subscript 2 space leftwards harpoon over rightwards harpoon space XY subscript 3 space semicolon space increment straight H space equals space minus space 30 space kJ comma space to space be space at$
equilibrium, the temperature should be

750 K
1000 K
1250 K
1250 K

15.

Three moles of an ideal gas expanded spontaneously into the vacuum. The work done will be

infinte
3 J
9 J
9 J

16.

The formation of the oxide ion O^2- (g), from oxygen atom requires first an exothermic and then an endothermic step as shown below,

$straight O space left parenthesis straight g right parenthesis space plus space straight e to the power of minus space rightwards arrow space straight O to the power of minus left parenthesis straight g right parenthesis semicolon space increment subscript straight f straight H to the power of straight o space equals space minus 141 space kJ space mol to the power of negative 1 end exponent straight O to the power of minus space left parenthesis straight g right parenthesis space plus straight e to the power of minus space rightwards arrow space straight O to the power of 2 minus end exponent space left parenthesis straight g right parenthesis semicolon space increment subscript straight f straight H to the power of straight o space equals plus 780 space kJ space mol to the power of negative 1 end exponent$
Thus, the process of formation of O^2- in the gas phase is unfavourable even though O^2- is isoelectronic with neon. It is due to the fact that

electron repulsion outweighs the stability gained by achieving a noble gas configuration
O^- ion has comparatively smaller size that oxygen atom
oxygen is more electronegative
oxygen is more electronegative

17.

For the gas phase, reaction,

PCl₅ (g) ⇌ PCl₃ (g) Cl₂ (g)
Which of the following conditions are correct?

Δ H = 0 and ΔS > 0
ΔH >0 and ΔS > 0
Δ H < 0 and ΔS < 0
Δ H < 0 and ΔS < 0

18.

Consider the following processes Δ H (kJ/mol)

1/2 A → +150
3B   → 2 C + D -125
E + A  → 2D +350

For B + D   → E + 2C, ΔH will be

525 kJ/mol
-175 kJ/mol
-325 kJ /mol
-325 kJ /mol

19.

Match List I (equation) with List II (types of the process) and select the correct option.

List I (Equations)		List II (Types of process)
A	K_P > Q	1	Non-spontaneous
B	ΔG^o < RT In Q	2	Equilibrium
C	K_P = Q	3	Spontaneous and endothermic
D	T> ΔH/ ΔS	4	Spontaneous

A

B

C

D

1

2

3

4
A B C D
3 4 2 1
A B C D
4 1 2 3
A B C D
4 1 2 3

20.

The heat of combustion of carbon to CO₂ is -395.5 kJ/mol. The heat released upon the formation of 35.2 g CO₂ from carbon and oxygen gas is

-315 kJ
+315 kJ
-630 kJ
-630 kJ

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Subject

NEET Chemistry : Thermodynamics

Multiple Choice Questions