Write down the formulae of
(i) sodium oxide
(ii) aluminium chloride
(iii) sodium sulphate
(iv) magnesium hydroxide.
The formulae of given compounds are:
(i) sodium oxide — Na2O
(ii) aluminium chloride — AlCl3
(iii) sodium sulphate — Na2SO4
(iv) magnesium hydroxide — Mg(OH)2