Question

Which of the following are decomposition reactions?

1. \[\ce{2KClO3 -> 2KCl + 3O2}\]
2. \[\ce{MgO + H2O -> Mg(OH)2}\]
3. \[\ce{2H2O -> H2 + O2}\]
4. \[\ce{Zn + CuSO4 -> ZnSO4 + Cu}\]

Options

• (i) and (ii)

• (iii) and (iv)

• (i) and (iii)

• (ii) and (iv)

Answer 1

(i) and (iii)

Explanation:

A decomposition reaction is one in which a single compound breaks down into simpler substances. In (i) and (iii), one compound splits into two or more products. (ii) is a combination reaction, and (iv) is a displacement reaction.