Chemistry 5070 · O Level · Formulae

Formulae — practice question

Aluminium ions, $\mathrm{Al^{3+}}$, react with sulfate ions, $\mathrm{SO_4^{2-}}$, to produce aluminium sulfate. Which row gives the correct empirical formula and ionic formula for aluminium sulfate?

  • Aempirical formula: $\mathrm{AlSO_4}$; ionic formula: $\mathrm{Al^{3+}SO_4^{2-}}$
  • Bempirical formula: $\mathrm{Al_2S_2O_8}$; ionic formula: $\mathrm{Al^{3+}(SO_4^{2-})_2}$
  • Cempirical formula: $\mathrm{Al_2S_3O_{12}}$; ionic formula: $\mathrm{Al_2^{3+}(SO_4^{2-})_3}$
  • Dempirical formula: $\mathrm{Al_3S_2O_8}$; ionic formula: $\mathrm{Al_3^{2+}(SO_4^{3-})_2}$

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