Question

A vessel at 1000 $K$ contains $C{O}_2$ with a pressure of 0.5 $atm$. Some of the $C{O}_2$ is converted into $CO$ on the addition of graphite. If the total pressure at equilibrium is 0.8 $atm$, the value of $K$ is_________.

• A. 1.8 $atm$
• B. 3 $atm$
• C. 0.3 $atm$
• D. 0.18 $atm$

Answer 1

The correct option is A 1.8 $atm$

The reaction is, $C{O}_2+C\to 2CO$

Initial pressure - $0.5atm0atm$
Final pressure - $(0.5-x)atm2xatm$

Total pressure at equilibrium = Partial pressures of $C{O}_2$ and $CO$

$=(0.5-x)+2x=0.8atm\left(given\right)$

$x=0.3$
$\therefore K_p=\frac{p_{CO}^2}{p_{C{O}_2}}=\frac{(0.6{)}^2}{0.2}=1.8atm$

So, the correct option is $A$