When zinc (Zn) reacts with hydrogen chloride (HCl), it undergoes a chemical reaction to form zinc chloride (ZnCl2) and hydrogen gas (H2). The balanced chemical equation for this reaction is:

Zn + 2HCl → ZnCl2 + H2

In this reaction, zinc atoms lose electrons to form positively charged zinc ions (Zn2+), while hydrogen ions (H+) from HCl gain electrons to form hydrogen gas (H2). The zinc chloride product is a salt that dissolves in water.

Here's a step-by-step explanation of the reaction:

1. Zinc atoms lose two electrons each to form Zn2+ ions:

Zn → Zn2+ + 2e-

2. Hydrogen ions from HCl gain electrons to form hydrogen gas:

2H+ + 2e- → H2

3. The Zn2+ and Cl- ions combine to form zinc chloride:

Zn2+ + 2Cl- → ZnCl2

The overall reaction can be summarized as:

Zn + 2HCl → ZnCl2 + H2

This reaction is an example of a single-displacement reaction, where one element (zinc) replaces another element (hydrogen) in a compound (hydrochloric acid).