Question

If $500mL$ of gas $A$ at $400$ torr and $666.6mL$ of $B$ at $600$ torr are placed in a $3$ litre flask, the pressure of the system will be

• A. 200 torr
• B. 100 torr
• C. 550 torr
• D. 366 torr

Answer 1

Answer: (A)

Applying Boyle's law $P_1{V}_1=P_2{V}_2$ for both gases
$\frac{500}{1000}\times 400=P\times 3$
$\Rightarrow P=\frac{200}{3}$
$600\times \frac{666.6}{1000}=P^{\prime }\times 3$
$\Rightarrow P^{\prime }=\frac{400}{3}$
$\Rightarrow P_T=P+P=\frac{200}{2}+\frac{400}{2}$
$=\frac{600}{2}=200$ torr