What happens when

(i) Magnesium burns in air with a dazzling light to form $\mathrm{MgO}$ and $\mathrm{Mg}_{3} \mathrm{~N}_{2}$.

$2 \mathrm{Mg}+\mathrm{O}_{2} \stackrel{\text { Buming }}{\longrightarrow} 2 \mathrm{MgO}$

$3 \mathrm{Mg}+\mathrm{N}_{2} \stackrel{\text { Buming }}{\longrightarrow} \mathrm{Mg}_{3} \mathrm{~N}_{2}$

(ii) Quick lime $(\mathrm{CaO})$ combines with silica $\left(\mathrm{SiO}_{2}\right)$ to form slag.

$\mathrm{CaO}+\mathrm{SiO}_{2} \stackrel{\text { beal }}{\longrightarrow} \mathrm{CaSiO}_{3}$

(iii) When chloride is added to slaked lime, it gives bleaching powder.

$\mathrm{Ca}(\mathrm{OH})_{2}+\mathrm{Cl}_{2} \stackrel{\Delta}{\longrightarrow} \mathrm{CaOCl}_{2}+\mathrm{H}_{2} \mathrm{O}$

Bleaching

powder

(iv) Calcium nitrate, on heating, decomposes to give calcium oxide.

$2 \mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2(s)} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{CaO}_{(s)}+4 \mathrm{NO}_{2(g)}+\mathrm{O}_{2(g)}$