Reactions of Dilute Acids with Metals

Reactions of Dilute Acids with Metals

General Knowledge:

  • When dilute acids react with metals they produce salt and hydrogen gas.
  • This reaction only happens with reactive metals including magnesium, zinc, and iron, but not with less reactive metals such as copper or silver.
  • The specific salt produced in the reaction depends on the type of acid and metal used.

Reaction with Hydrochloric Acid:

  • Reaction of a metal with hydrochloric acid always produces a type of chloride salt.
  • For instance, if zinc is reacted with hydrochloric acid, the equation becomes:
    Zn (s) + 2HCl (aq) -> ZnCl2 (aq) + H2 (g)
  • The hydrogen gas given off can be tested using a lit splint, which should create a squeaky pop sound.

Reaction with Sulfuric Acid:

  • When a metal reacts with sulfuric acid, a type of sulphate salt is produced.
  • For example, when magnesium is reacted with sulfuric acid, the equation is:
    Mg (s) + H2SO4 (aq) -> MgSO4 (aq) + H2 (g)
  • The test for hydrogen gas remains the same, using a lit splint to check for the pop sound.

Reaction with Nitric Acid:

  • Nitric acid is a bit peculiar as it produces oxides of nitrogen instead of hydrogen when it reacts with metals.
  • Because of this, nitric acid is not typically used in testing for gas produced in reactions of acids with metals.
  • An example reaction with zinc:
    Zn (s) + 2HNO3 (aq) -> Zn(NO3)2 (aq) + 2NO2 (g) + 2H2O (l)

More reactive metals, like potassium (K), sodium (Na) and calcium (Ca) react vigorously with acids, and it’s dangerous to carry out these reactions.