What happens when zinc granules are added to hydrochloric acid?

When zinc (Zn) is added to hydrochloric acid (HCl), a single displacement reaction occurs:

Zn (s) + 2HCl (aq) → ZnCl₂ (aq) + H₂ (g)

Observation:

• Effervescence (bubbles) due to liberation of hydrogen gas.
• The solution becomes zinc chloride (ZnCl₂).
• Heat is released (exothermic reaction).

Experimentally:

• If a burning matchstick is brought near the test tube mouth, a “pop sound” confirms hydrogen gas.
• This reaction is often demonstrated in chemistry labs to show reactivity of metals with acids.

Practical Applications:

• Zinc granules + HCl are used in labs to prepare hydrogen gas.
• Zinc chloride formed is useful in batteries, flux, and as a dehydrating agent.

Key Takeaways:

• Reaction: Zn + HCl → ZnCl₂ + H₂↑
• Hydrogen gas is liberated.
• Exothermic, vigorous effervescence.