Q: How to write a balanced equation for double-replacement reaction between sodium sulfide and hydrogen chloride?

Flexi Says: When solutions of sodium sulfide and hydrochloric acid are mixed, the products of the reaction are aqueous sodium chloride and hydrogen sulfide gas. The reaction is:
Na₂S (aq) + 2HCl (aq) → 2NaCl (aq) + H₂S (g)
This is an example of a double-replacement reaction, in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.