Vapour density of a gas is $5.6$,volume of $5.6 \ g$ of it at $STP$ is ............... $L$

For which of the following reactions,the degree of dissociation cannot be calculated from the vapour density data?
$I. \ 2HI_{(g)} \rightleftharpoons H_{2(g)} + I_{2(g)}$
$II. \ 2NH_{3(g)} \rightleftharpoons N_{2(g)} + 3H_{2(g)}$
$III. \ 2NO_{(g)} \rightleftharpoons N_{2(g)} + O_{2(g)}$
$IV. \ PCl_{5(g)} \rightleftharpoons PCl_{3(g)} + Cl_{2(g)}$

Ammonium carbonate,when heated to $200\, ^oC$,dissociates into a mixture of $NH_3$ and $CO_2$ vapors with a vapor density of $13.0$. What is the degree of dissociation of ammonium carbonate?

The dissociation equilibrium of a gas $AB_{2}$ can be represented as:
$2AB_{2(g)} \rightleftharpoons 2AB_{(g)} + B_{2(g)}$
The degree of dissociation is $x$ and is small compared to $1$. The expression relating the degree of dissociation $(x)$ with equilibrium constant $K_P$ and total pressure $P$ is:

For the equilibrium reaction $N_2O_{4(g)} \rightleftharpoons 2NO_{2(g)}$,the value of $K_p$ is $2$. Calculate the percentage dissociation of $N_2O_{4(g)}$ at a total pressure of $0.5 \ atm$. (in $\%$)

$A$ gas has the formula $[CO]_x$. If its vapor density is $70$,what is the value of $x$?