• # question_answer Two separate bulbs contain ideal gases A and B. The density of gas A is twice that of gas B. The molecular mass of A is half that of gas B. The two gases are at the same temperature. The ratio of the pressure of A to that of gas B is [BHU 1994] A)                 2              B)                 1/2 C)                 4              D)                 ¼

${{d}_{a}}=2{{d}_{b}}$ ; $2{{M}_{a}}={{M}_{b}}$                    $PV=nRT=\frac{m}{M}RT$;  $P=\frac{m}{V}.\frac{RT}{M}=\frac{dRT}{M}$                              $\frac{{{P}_{a}}}{{{P}_{b}}}=\frac{{{d}_{a}}}{{{d}_{b}}}\frac{{{M}_{b}}}{{{M}_{a}}}=\frac{2{{d}_{b}}}{{{d}_{b}}}\times \frac{2{{M}_{a}}}{{{M}_{a}}}=4$