Types of reactions – decomposition, precipitation, neutralisation, displacement- Decomposition: A decomposition reaction is when a complex molecule breaks down to make simpler ones.AB ---> A + BExample - electrolysis of water to make oxygen and hydrogen gas:2 H2O ---> 2 H2 + O2

- Precipitation: When a soluble transition metal compound is mixed with sodium hydroxide solution then there is displacement reaction. The sodium is more reactive and displaces the transition metal from its compound. The transition metal hydroxide is produced as a result. As this is insoluble in water it appears as a solid in the liquid. A solid produced in a liquid in this way is called a precipitate.Example: Cu2+ + NaOH ---> Cu(OH)2 (light blue)

- Neutralisation: Reaction of acid and base always produces salt and waterExample - HCl + NaOH --> NaCl + HOH

- Displacement: Part of one reactant is replaced by another reactantExample: (single displacement) AB + C → AC + B(double displacement) AB + CD → AD + CB

Properties of acids and bases