(અહીં : $SrCO_{3(s)} \rightleftharpoons SrO_{(s)}+ CO_{2(g)} \,, K_p=1.6\,atm$)
$\mathrm{K}_{\mathrm{p}}=\mathrm{P}_{\mathrm{CO}_{2}}$
maximum pressure of $\mathrm{CO}_{2}=1.6\; \mathrm{atm}$
$\mathrm{P}_{1} \mathrm{V}_{1}=\mathrm{P}_{2} \mathrm{V}_{2}$
$0.4 \times 20=1.6 \mathrm{V}_{2}$
$\mathrm{V}_2=5 \,\mathrm{L} \quad$