Question

A cylinder contains 2kg of air at a pressure of 10${}^5$Pa. If 2 kg more air is pumped into it, keeping the temperature constant, the pressure will be

• A. ${10}^{10}Pa$
• B. $2\times {10}^{5}Pa$
• C. ${10}^{5}Pa$
• D. $0.5\times {10}^{5}Pa$

Answer 1

The correct option is B $2\times {10}^{5}Pa$

Since both volume and Temperature is constant,

$\frac{P}{n}=constant=\frac{P}{m}n=no.ofmoles=\frac{massofair\left(m\right)}{Molecularweightofwater\left(M\right)}$

$\frac{{10}^5}{2}=\frac{P}{(2+2)}\Rightarrow P=2\times {10}^{5}Pa$

Hence, Option B is correct