Question

The standard Gibbs energy channge 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, $△G^o=2494.2J$
$Q=\frac{\left[B\right]\left[C\right]}{[A{]}^2}=\frac{2\times \frac{1}{2}}{\left(\frac{1}{2}\right)}=4$

$\therefore$ We know, $△G=△G^o$ + RT ln Q
= 2494.2 + 8.314 $\times$ 300 ln 4
= 28747.27 J (+ ve value)
Also, we have $△G=RTln\frac{Q}{K}$
If $△$ G is positive, Q > K
Therefore, reaction shifts in reverse direction. ​​​