The vapour density of ${\mathrm{N}}_2{\mathrm{O}}_4$ at a certain temperature is $40.$ What is the percentage dissociation of ${\mathrm{N}}_2{\mathrm{O}}_4$ at this temperature?

The ratio of the partial pressure of ${\mathrm{O}}_2$ at equilibrium in the given reactions at same temperature is:

${\mathrm{Ag}}_2{\mathrm{O}}_{\left(\mathrm{s}\right)}\rightleftharpoons 2{\mathrm{Ag}}_{\left(\mathrm{s}\right)}+{}_2{}^1\mathrm{O}_{2\left(\mathrm{g}\right)}$

$2{\mathrm{Ag}}_2{\mathrm{O}}_{\left(\mathrm{s}\right)}\rightleftharpoons 4{\mathrm{Ag}}_{\left(\mathrm{s}\right)}+{\mathrm{O}}_{2\left(\mathrm{g}\right)}$

At constant pressure, the addition of argon to, ${\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3\left(\mathrm{g}\right)$ will:

If the equilibrium constant for the reaction, ${\mathrm{P}}_{4\left(\mathrm{g}\right)}+6{\mathrm{Cl}}_{2\left(\mathrm{g}\right)}\rightleftharpoons 4{\mathrm{PCl}}_{3\left(\mathrm{g}\right)}$ is $0.125$. The value of equilibrium for the reaction, $4{\mathrm{PCl}}_{3\left(\mathrm{g}\right)}\rightleftharpoons {\mathrm{P}}_{4\left(\mathrm{g}\right)}+6{\mathrm{Cl}}_{2\left(\mathrm{g}\right)}$ will be: