The vapor density of a volatile substance with respect to $CH_4$ $(CH_4 = 1)$ is $4$. What is its molecular weight?

The equilibrium constant for the decomposition of $H_2O_{(g)}$: $H_2O_{(g)} \rightleftharpoons H_{2(g)} + \frac{1}{2} O_{2(g)}$ $(\Delta G^{\circ} = 92.34 \ kJ \ mol^{-1})$ is $8.0 \times 10^{-3}$ at $2300 \ K$ and the total pressure at equilibrium is $1 \ bar$. Under this condition,the degree of dissociation $(\alpha)$ of water is $............ \times 10^{-2}$ (nearest integer value). [Assume $\alpha$ is negligible with respect to $1$]

Phosphorus pentachloride dissociates as follows,in a closed reaction vessel:
$PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$
If total pressure at equilibrium of the reaction mixture is $P$ and degree of dissociation of $PCl_5$ is $x,$ the partial pressure of $PCl_3$ will be:

At temperature,$T$,a compound $AB_{2(g)}$ dissociates according to the reaction; $2AB_{2(g)} \rightleftharpoons 2AB_{(g)} + B_{2(g)}$ with a degree of dissociation $x$,which is small compared with unity. The expression for $K_p$,in terms of $x$ and the total pressure,$P$ is

For the reaction $A \rightleftharpoons \frac{1}{2} B + C$,the degree of dissociation $\alpha$ in terms of vapour density $D_t$ (theoretical) and $D_o$ (observed) is given by:

At $STP$,the density of air is $0.001293 \ g \ mL^{-1}$. Its vapour density is $---$.