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.

Explanation

To solve the problem, we need to identify the metal compound A that reacts with dilute hydrochloric acid (HCl) to produce effervescence and a gas that extinguishes a burning candle. We also know that one of the products formed is calcium chloride (CaCl₂).

### Step-by-Step Solution:

1. **Identify the Reaction**:
- The metal compound A is likely to be calcium carbonate (CaCO₃) because it reacts with hydrochloric acid to produce carbon dioxide (CO₂), which is the gas that extinguishes a burning candle.

2. **Write the Reactants**:
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