Acids and Reactive Metals

Full Notes

General Reaction Pattern

When a reactive metal (like magnesium, zinc, or iron) reacts with a dilute acid, a single displacement reaction occurs:

Metal + Acid → Salt + H₂(g)

The salt formed depends on the acid used:

For Example:

• HCl forms chloride salts
• H₂SO₄ forms sulfate salts

Example Equations

With Hydrochloric Acid (HCl):

• Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)
• Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

With Sulfuric Acid (H₂SO₄):

• Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂(g)
• Ca(s) + H₂SO₄(aq) → CaSO₄(aq) + H₂(g)

Summary

• Reactive metals + dilute acids → salt + hydrogen gas.
• The salt depends on the acid (HCl → chloride, H₂SO₄ → sulfate).
• Characteristic observation: effervescence (fizzing) from H₂ gas.