Chemical Equilibrium Question 1

Question 1 - 24 January - Shift 1

For independent process at $300 K$.

Process $\Delta \mathbf{H} / \mathbf{k J ~ m o l}^{\mathbf{- 1}}$ $\Delta \mathbf{S} / \mathbf{J}^{-\mathbf{1}}$
A -25 80
B -22 40
C 25 -50
D 22 20

The number of non-spontaneous process from the following is___________

Show Answer

Answer: (2)

Solution:

Formula: Criteria of spontaneity

$\Delta G=\Delta H-T \Delta S$

A : $\Delta G(J mol^{-1})=-25 \times 10^{3}+80 \times 300:-ve$

B : $\Delta G(J mol^{-1})=-22 \times 10^{3}-40 \times 300:-ve$

$C: \Delta G(J mol^{-1})=25 \times 10^{3}+300 \times 50:+ve$

$D: \Delta G(J mol^{-1})=22 \times 10^{3}-20 \times 300:+ve$

Processes C and D are non-spontaneous.