At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?
Density, d = Mp/RT
When T and D are same and R is constant, then
$p_{ 1 }$ $M_{ 1 }$ = $p_{ 2 }$ $M_{ 2 }$
2 bar x $M_{ 1 }$ = 5 bar x 28 u
Molecular mass of unknown oxide,
$M_{ 1 }$ = 5 bar x 28/2 bar = 70 u