Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.

Metal compound A reacts with dilute hydrochloric acid to produce Calcium Chloride, the gas evolved CO₂ with brisk effervescence. Hence, metal A should be Calcium Carbonate.

Hence, the reaction between Calcium Carbonate and HCl is

CaCO₃ (s) + 2HCl (Aq) → CaCl₂( Aq) + CO₂ (g) + H₂O (l)