Question

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

• 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

The correct option is B Reverse direction because $Q>K_c$

Given, $\Delta G^{\circ }=2494.2JQ=\frac{\left[B\right]\left[C\right]}{[A{]}^2}=\frac{2\times \frac{1}{2}}{{\left(\frac{1}{2}\right)}^2}=4\therefore \text{We know},\Delta G=\Delta G^{\circ }+RTInQ=2494.2+8.314\times 300\text{ln}4=28747.27J(+\text{ve value})$
Also, we have $\Delta G=RT\text{ln}\frac{Q}{K}$
If $\Delta G$ is positive, $Q>K_c$
Therefore, reaction shifts in reverse direction.