What is the vapor density of a mixture containing $20\%\, NO_2$ by volume and $N_2O_4$?

Degree of dissociation of an electrolyte does not depend on

If the density of a gas at $STP$ is $0.178 \, g/L$,find its vapor density.

The vapor density of a gas is $16$. If the ratio of specific heat at constant pressure to specific heat at constant volume is $1.4$,find its atomic weight.

At a certain temperature,the vapour density of $N_2O_4$ is $30$. Find the percentage of dissociation of $N_2O_4$ at this temperature.

Gaseous $N_2O_4$ dissociates into gaseous $NO_2$ according to the reaction:
$N_2O_{4(g)} \rightleftharpoons 2NO_{2(g)}$
At $300 \ K$ and $1 \ atm$ pressure,the degree of dissociation of $N_2O_4$ is $0.2$. If one mole of $N_2O_4$ gas is contained in a vessel,then the density of the equilibrium mixture is.......$g/L$