Question

If $500ml$ of a gas $A$ at $1000torr$ and $1000ml$ of gas $B$ at $800torr$ are placed in a $2L$ container, the final pressure will be :

• A. $100torr$
• B. $650torr$
• C. $1800torr$
• D. $2400torr$

Answer 1

Answer: (B)

$650torr$

The number of moles of A, $n=\frac{PV}{RT}=\frac{500\times 1000}{RT}$

The number of moles of B, $n^{\prime }=\frac{PV}{RT}=\frac{1000\times 800}{RT}$

The final pressure, $P=\frac{nRT}{V}=\frac{\frac{500\times 1000}{RT}+\frac{1000\times 800}{RT}}{2000}RT=\frac{500000+800000}{2000}=650$ torr.

Therefore, the correct option is $B$