Question

A solution of a substance ‘X’ is used for white washing.
(i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.

Answer 1

(i) The substance ‘X’ is calcium oxide. Its chemical formula is CaO.
(ii) Calcium oxide reacts vigorously with water to form calcium hydroxide (slaked lime).
CaO (s)                              + H₂O (l) → Ca(OH)₂ (aq)
Calcium Oxide (Quick Lime) + Water    → Calcium Hydroxide (Slaked Lime)