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

The vapor density of a gas is $11.2$. At $N.T.P.$,$11.2 \ g$ of this gas occupies a volume of ............. $litres$.

For the reaction $A_{3(g)} \rightleftharpoons 3A_{(g)}$,the initial moles of $A_3$ is $a$. If $\alpha$ is the degree of dissociation of $A_3$,then the total number of moles at equilibrium will be:

Phosphine decomposes at $300 \ K$ and $3 \ atm$ as
$4PH_{3(g)} \rightleftharpoons P_{4(g)} + 6H_{2(g)}$
Calculate the vapour density of phosphine if it dissociates to the extent of $30 \%$.

Ammonium carbamate $(NH_2COONH_4)$ when heated to $200\,^{\circ}C$ gives a mixture of $NH_3$ and $CO_2$ with a vapour density of $13.0$ at equilibrium. What is the degree of dissociation of ammonium carbamate?

For completely dissociated $NH_4Cl$,the vapour density is ........