Reactions of Acids with Metals

Two acids that are used a lot in chemistry are:

  • Hydrochloric acid (HCl)
  • Sulfuric acid (H2SO4)

A common characteristic of all acids is that they contain hydrogen. Metals above hydrogen in the reactivity series can displace hydrogen from acids. A general rule for the reaction between acids and metals is:

Acid + Metal Salt + Hydrogen

So, when acids react with metals, they form a salt and hydrogen gas. The salt produced depends on the acid used in the reaction and the metal it reacts with.

  • Hydrochloric acid produces salts that end in ‘chloride’
  • Sulfuric acid produces salts that end in the word ‘sulfate’

Let’s look at how hydrochloric acid and sulfuric acid react with magnesium, zinc and iron.

MetalHydrochloric acidSulfuric acid
Magnesium (Mg)2HCl + Mg → MgCl2 + H2 H2SO4 + Mg ⟶ MgSO4 + H2
Zinc (Zn)2HCl + Zn → ZnCl2 + H2 H2SO4 + Zn ⟶ ZnSO4 + H2
Iron (Fe)2HCl + Fe → FeCl2 + H2 H2SO4 + Fe ⟶ FeSO4 + H2