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.
During the chemical reaction, the evolved gas extinguishes a burning candle which means the gas is carbon dioxide. Carbon dioxide is formed when dilute hydrochloric acid reacts with a metal carbonate (or metal hydrogen carbonate) producing effervescence. Since, one of the compounds formed during this reaction is calcium chloride, it means the metal compound is calcium carbonate (It cannot be calcium hydrogen carbonate because calcium hydrogen carbonate is found only in solution, it is also unstable to exist as a solid). Hence, the compound A is calcium carbonate. The chemical reaction is written as follows
CaCO3 (s) + 2HCL (aq) → CaCl2 (aq) + CO2 (g) + H2O (I)