- A salt is a compound that is formed when the hydrogen atom in an acid is replaced by a metal.
- For example if we replace the H in HCl with a potassium atom, then the salt potassium chloride is formed, KCl.
- Salts are an important branch of chemistry due to the varied and important uses of this class of compounds.
- These uses include fertilisers, batteries, cleaning products, healthcare products and fungicides.
- The name of a salt has two parts.
- The first part comes from the metal, metal oxide or metal carbonate used in the reaction.
- The second part comes from the acid.
- The name of the salt can be determined by looking at the reactants
- For example hydrochloric acid always produces salts that end in chloride and contain the chloride ion, Cl–.
- Other examples:
- Sodium hydroxide reacts with hydrochloric acid to produce sodium chloride.
- Zinc oxide reacts with sulfuric acid to produce zinc sulfate.
Reactions of Acids and Metals
- Only metals above hydrogen in the reactivity series will react with dilute acids.
- When acids react with metals they form a salt and hydrogen gas:
Reactions of Acids with Metal Oxides and Metal Hydroxides
- Metal oxides and metal hydroxides act as bases.
- When they react with acid, a neutralisation reaction occurs.
- In all acid-base neutralisation reactions, salt and water are produced.
Reactions of Acids with Metal Carbonates
- Acids will react with metal carbonates to form the corresponding metal salt, carbon dioxide and water.