A reaction occurs spontaneously if
TS < H and both H and S are + ve
TS > H and both H and S are + ve
TS = H and both H and S are + ve
TS > H and H and is +ve and S is -ve
If ΔE is the heat of reaction for
C2H5OH(I) + 3O2(g) → 2CO2 (g) + 3H2O(I)
at constant volume, the ΔH (heat of reaction at constant pressure), then the correct relation is
ΔH = ΔE + RT
ΔH = ΔE - RT
ΔH = ΔE - 2RT
ΔH = ΔE + 2RT
In a closed insulated container a liquid is stirred with a paddle to increase the temperature, which of the following is true ?
E = W ≠ 0, q = 0
E = W = 0, q = 0
E =0,W =q ≠ 0
W =0,E =q ≠ 0
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)
(II) and (III)
Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction ?
Exothermic and decreasing disorder
Endothermic and increasing disorder
Exothermic and increasing disorder
Endothermic and decreasing disorder
The entropy change in the fusion of one mole of a solid melting at 27o C (latent heat of fusion is 2930 J mol-1 ) is
9.77 J K-1 mol-1
10.73 J K-1 mol-1
2930 J K-1 mol-1
108.5 J K-1 mol-1
For the gas phase reaction,
PCI5 (g) PCI3(g) + CI2(g)
Which of the following conditions are correct ?
ΔH = 0 and ΔS < 0
ΔH > 0 and ΔS > 0
ΔH < 0 and ΔS < 0
ΔH > 0 and ΔS < 0
Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is
Ssystem + Ssurrounding > 0
Ssystem - Ssurrounding > 0
Ssystem > 0 only
Ssurrounding > 0 only
Equal volume of molar hydrochloric acid and sulphuric acid are neutralised by dil NaOH solution and x kcal and y kcal of heat are liberated respectively. Which of the following is true ?
x = y
y = 2x
x = 2y
None of these
Identify the correct statement regarding entropy.
At absolute zero temperature, entropy of a perfectly crystalline substance is taken to be zero
At absolute zero temperature, the entropy of a perfectly crystalline substance is +ve
At absolute zero temperature, the entropy of all crystalline substances is to be zero
At 0o C, the entropy of a perfectly crystalline substance is taken to be zero