CBSE 2026 · Region 2 · Set 3 · Q19

Which of the following are decomposition reactions?

(i)

$\displaystyle 2 \mathrm{KClO}_{3} \longrightarrow 2 \mathrm{KCl}+3 \mathrm{O}_{2}$

(ii)

$\displaystyle \mathrm{MgO}+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{Mg}(\mathrm{OH})_{2}$

(iii)

$\displaystyle 2 \mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{H}_{2}+\mathrm{O}_{2}$

(iv)

$\displaystyle \mathrm{Zn}+\mathrm{CuSO}_{4} \longrightarrow \mathrm{ZnSO}_{4}+\mathrm{Cu}$