Question

A gas occupies a volume of $250$ ml at $745$ mm Hg and ${25}^{\circ }$C. What additional pressure is required to reduce the gas volume to $200$ ml at the same time?

• A. $180.25$ mm
• B. $200.9$ mm
• C. $186.25$ mm
• D. $189.4$ mm

Answer 1

The correct option is C $186.25$ mm

Given: $P_1=745$ mm Hg

$V_1=250$ ml

$V_2=200$ ml

$\therefore$ By Boyle's law as the temperature is constant.

$P_2=\frac{P_1{V}_1}{V_2}=\frac{745\times 250}{200}=931.25$ mm Hg

Additional pressure required $=931.25-745=186.25$ mm

Hence, the correct answer is option $\text{C}$.