Reactions of Acids

Reactions of acids with metals

• Only metals above hydrogen in the reactivity series will react with dilute acids

• The more reactive the metal then the more vigorous the reaction will be

• Metals that are placed high on the reactivity series such as potassium and sodium are very dangerous and react explosively with acids

• When acids react with metals they form a salt and hydrogen gas:

• The general equation is:

  • metal + acid ⟶ salt + hydrogen

• Some examples of metal-acid reactions and their equations are given below:

Acid-Metals Reactions Table

• In general, we can summarise the reaction of a metal that forms a +2 ion as follows:

Reaction of acids with oxides & hydroxides

• When an acid reacts with an oxide or hydroxide, a neutralisation reaction occurs

• Metal oxides and metal hydroxides act as bases

• In all acid-base neutralisation reactions, a salt and water are produced:

  • acid + base ⟶ salt + water

• The identity of the salt produced depends on the acid used and the positive ions in the base

• Hydrochloric acid produces chlorides, sulfuric acid produces sulfate salts and nitric acid produces nitrates

• The following are some specific examples of reactions  between acids and metal oxides / hydroxides:

  • 2HCl + CuO ⟶ CuCl2 + H2O
  • H2SO4 + 2NaOH ⟶ Na2SO4 + 2H2O
  • HNO3 + KOH ⟶ KNO3 + H2O

• In general, we can summarise the reaction of metals and bases as follows:

Reactions of Acids with Metal Carbonates

• Acids will react with metal carbonates to form the corresponding metal salt, carbon dioxide and water
• These reactions are easily distinguishable from acid – metal oxide/hydroxide reactions due to the presence of effervescence caused by the carbon dioxide gas