Question

In the reaction, $C\left(s\right)+C{O}_2\left(g\right)\rightleftharpoons 2CO\left(g\right),$ the equilibrium pressure is 12 atm. If 50% of $C{O}_2$ reacts then $K_p$ will be:

• A. 12 atm
• B. 16 atm
• C. 20 atm
• D. 24 atm

Answer 1

The correct option is B 16 atm

Reaction
$\begin{array}{cccccc}& C\left(s\right)& +& C{O}_2\left(g\right)& \rightleftharpoons & 2CO\left(g\right)\\ \text{Initial Pressure}& & & P& & 0\\ \text{At equilibrium}& & & P-\frac{P}{2}& & 2\times \frac{P}{2}\\ \left(50\%C{O}_{2}react\right)& & & \frac{P}{2}& & P\end{array}$
Total pressure at equilibrium,
$\frac{3P}{2}=12atm\Rightarrow P=8atm$
$\Rightarrow K_P=\frac{[P_{CO}{]}^2}{P_{C{O}_2}}=\frac{P^2}{P/2}$
$\Rightarrow K_p=2P=2\times 8=16atm$
Therefore, the correct option is (b).