$0.4 \mathrm{moles}$ of aluminium sulphate, ${\mathrm{Al}}_2{\left({\mathrm{SO}}_4\right)}_3$, are dissolved in water and the volume of the solution was made up to $500 {\mathrm{cm}}^3$. Which one of these statements is correct?

A. The solution contains a total of $2$ moles of ions.

B. The concentration of aluminium ions is $0.8 \mathrm{mol} {\mathrm{dm}}^{-3}$.

C. The concentration of sulphate ions in solution is $1.2 \mathrm{mol} {\mathrm{dm}}^{-3}$.

D. The solution contains a total of $4$ moles of ions.

$50 {\mathrm{cm}}^3$ of a gaseous hydride of phosphorus, ${\mathrm{PH}}_{\mathrm{n}}$ reacts with exactly $150 {\mathrm{cm}}^3$ of chlorine, ${\mathrm{Cl}}_2$, to form liquid phosphorous trichloride and $150 {\mathrm{cm}}^3$ of hydrogen chloride gas, $\mathrm{HCl}$. How many moles of chlorine react with $1$ mole of the gaseous hydride?

$50 {\mathrm{cm}}^3$ of a gaseous hydride of phosphorus, ${\mathrm{PH}}_{\mathrm{n}}$ reacts with exactly $150 {\mathrm{cm}}^3$ of chlorine, ${\mathrm{Cl}}_2$, to form liquid phosphorous trichloride and $150 {\mathrm{cm}}^3$ of hydrogen chloride gas, $\mathrm{HCl}$. Deduce the formula of the phosphorus hydride.

$50 {\mathrm{cm}}^3$ of a gaseous hydride of phosphorus, ${\mathrm{PH}}_{\mathrm{n}}$ reacts with exactly $150 {\mathrm{cm}}^3$ of chlorine, ${\mathrm{Cl}}_2$, to form liquid phosphorous trichloride and $150 {\mathrm{cm}}^3$ of hydrogen chloride gas, $\mathrm{HCl}$. Write a balanced equation for the reaction.

What is the volume of carbon dioxide produced when $14 \mathrm{g}$ of ethene, ${\mathrm{C}}_2{\mathrm{H}}_4$, reacts with excess oxygen? (${\mathrm{M}}_{\mathrm{r}}$ ethene$=28$).

${\mathrm{C}}_2{\mathrm{H}}_4\left(\mathrm{g}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{CO}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$.