It is known that a white powder is a mixture of magnesium oxide and aluminium oxide. $100\ \text{cm}^3$ of $2\ \text{mol dm}^{-3}$ NaOH(aq) is exactly sufficient to dissolve the aluminium oxide in $x$ grams of the mixture. The equation for this reaction is: $\text{Al}_2\text{O}_3 + 2\text{OH}^- + 3\text{H}_2\text{O} \rightarrow 2\text{Al(OH)}_4^-$ $800\ \text{cm}^3$ of $2\ \text{mol dm}^{-3}$ HCl(aq) is exactly sufficient to dissolve all the oxide in $x$ grams of the mixture. The equations are shown: $\text{Al}_2\text{O}_3 + 6\text{H}^+ \rightarrow 2\text{Al}^{3+} + 3\text{H}_2\text{O}$ $\text{MgO} + 2\text{H}^+ \rightarrow \text{Mg}^{2+} + \text{H}_2\text{O}$ What number of moles of each oxide are contained in $x$ grams of the mixture?
- Aaluminium oxide $0.05$, magnesium oxide $0.25$
- Baluminium oxide $0.05$, magnesium oxide $0.50$
- Caluminium oxide $0.10$, magnesium oxide $0.25$
- Daluminium oxide $0.10$, magnesium oxide $0.50$