Question

If $K_P$ of an equilibrium $CaC{O}_3\left(s\right)\rightleftharpoons CaO\left(s\right)+C{O}_2\left(g\right)$ is 1.5 atm at ${20}^{o}C$ then the moles of CaO formed if excess $CaC{O}_3\left(s\right)$ is being placed in a 1 lt of closed container containing $C{O}_2$ gas at 0.5 atm pressure at same temperature is:

• A. $\frac{1}{56}$
• B. $\frac{1}{24}$
• C. $\frac{1}{12}$
• D. $\frac{1}{13}$

Answer 1

The correct option is B $\frac{1}{24}$

The ideal gas equation is $PV=nRT.$
Substitute values in the above expression to find the number of moles of carbon dioxide.
$0.5\times 1=n\times 0.082\times 293$
Thus the number of moles of carbon dioxide $n=\frac{1}{24}$.
This is equal to the number of moles of calcium oxide.