Question

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.

Answer 1

• The gas that produces effervescence and extinguishes a burning candle is carbon dioxide.
• Dilute acids give $C{O}_2$ with metal carbonates.
• Since one of the compounds formed is calcium chloride $\left(CaC{l}_2\right)$ thus, the metal compound (A) is a carbonate of calcium metal.
• Calcium carbonate $\left(CaC{O}_3\right)$ reacts with dilute hydrochloric acid to form calcium chloride, carbon dioxide $\left(C{O}_2\right)$, and water $\left(H_{2}O\right)$. The balanced chemical equation for the reaction is given as,

$CaC{O}_3\left(s\right)+HCl\left(aq\right)\to CaC{l}_2\left(aq\right)+C{O}_2\left(g\right)+H_{2}O\left(l\right)$