A solution of a substance ‘X’ is used for whitewashing.
(i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.
Answer:
(i) Name the substance ‘X’ and write its formula.
The substance ‘X’ used for whitewashing is quick lime.
Name of X: Calcium oxide
Formula: CaO
(ii) Reaction of ‘X’ (Calcium oxide) with water:
When calcium oxide (CaO) reacts with water (H₂O), it forms calcium hydroxide (Ca(OH)₂), also known as slaked lime. This reaction releases a lot of heat (it’s exothermic).
CaO + H2O → Ca(OH)2 + Heat