Question

The standard Gibbs energy change at $300 \,K$ for the reaction $2 A \rightleftharpoons B + C$ is $2494.2]$. At a given time, the composition of the reaction mixture is $[ A ]=\frac{1}{2},[ B ]=2$ and $[ C ] =\frac{1}{2} .$ The reaction proceeds in the :
$[ R =8.314\, J / \,K /\, mol , e =2.718]$

• A. forward direction because $Q > K_c$
• B. reverse direction because $ Q> K_c$
• C. forward direction because $Q < K_c$
• D. reverse direction because $Q < K_c$

Answer 1

Answer: (B)

Given, $\quad \Delta G^{\circ}=2494.2 J$
$\therefore$ We know,
$\Delta G =\Delta G^{\circ}+R T \ln Q $
$=2494.2+8.314 \times 300 \ln 4$
$=28747.27 J (+\text { ve value })$
Also, we have $\quad \Delta G=R T \ln \frac{Q}{K}$
If $\Delta G$ is positive, $Q>K$
Therefore, reaction shifts in reverse direction.