Browse Questions

# Two separate bulbs contain gas A and gas B. The density of gas A is twice as that of B. The molecular mass of A is $\large\frac{1}{2}$ as that of B. If temperature is constant, the ratio of the pressure of A and B is :

$(a)\;1:1\qquad(b)\;1:2\qquad(c)\;4:1\qquad(d)\;2:1$

Toolbox:
• Density of the gas $= \large\frac{Pressure\; \times Molecular \; mass}{RT}$
$d = \large\frac{PM}{RT}$
$\large\frac{d_A}{d_B} = 2$
$=\large\frac{P_A\times M_A}{P_B\times M_B}$
$=\large\frac{P_A}{P_B}\times \large\frac{1}{2}$
$\therefore \large\frac{P_A}{P_B} = 4$
Hence the ratio is 4:1
edited Mar 18, 2014