Question

A gas 1g at 4 bar pressure. If we add 2g of gas B then the total pressure inside the container is 6 bar. Which of the following is true ?

• A. $M_A=2M_B$
• B. $M_B=2M_A$
• C. $M_A=4M_B$
• D. $M_B=4M_A$

Answer 1

The correct option is D $M_B=4M_A$

$\frac{n_1}{p_1}=\frac{n_2}{p_2}$
$\frac{\frac{1}{M_A}}{4}=\frac{\frac{1}{M_A}+\frac{2}{M_B}}{6}$

$\frac{6}{M_A}=\frac{4}{M_A}+\frac{8}{M_B}$

$\frac{2}{M_A}=\frac{8}{M_B}$

$M_B=4M_A$