Question

The equilibrium constant, $K_p$ for the reaction, $2NOCl\left(g\right)\rightleftharpoons 2NO\left(g\right)+C{l}_2\left(g\right)$ is $0.95\times {10}^{-6}$ at $298K$. The standard Gibb's free energy charges, $\Delta G^o$ at $298K$ will be: $(R=2cal{K}^{-1}mol{e}^{-1})$ $(\log 6.95=0.8420)$

• A. $4.912kcal$
• B. $14.74kcal$
• C. $7.3kcal$
• D. $9.825kcal$

Answer 1

Answer: (A), (D)

$4.912kcal$
$9.825kcal$

Solution:-

As we know that the relation between $\Delta G^0$ and equillibrium constant $K_c$ is given as-

$\Delta G^0=-2.303RT\log K_p$

Given:-

$R=2cal/mol-K$

$log\left(6.95\right)=0.8420$

$K_p=0.95\times {10}^{-6}=9.5\times {10}^{-7}$

$T=298K$

$\therefore \Delta G^0=-2.303\times 2\times {10}^{-3}\times 298\times \log (9.5\times {10}^{-7})$

$\Rightarrow \Delta G^0=-1.3(\log \left(9.5\right)-7\log 10)$

$\Rightarrow \Delta G^0=-\mathrm{1.372.588}(2.25-7)=6.517kcal$