State the observations when sodium hydroxide solution is added, first a little and then in excess, to zinc sulphate solution, and write the equations.

A white precipitate is formed when sodium hydroxide is added to a salt solution, and it does not dissolve in excess. Name the cation and state one further test.

Name the gas evolved when sodium hydroxide solution is warmed with an ammonium salt, and state how it is identified.

A salt solution gives a dirty green precipitate with sodium hydroxide solution, insoluble in excess. Identify the cation and write the equation for the reaction.

A salt solution gives a white precipitate with sodium hydroxide solution which dissolves in excess to give a colourless solution. Identify the two cations this could be and state how ammonium hydroxide distinguishes between them.

State what is observed when ammonium hydroxide solution is added, first a little and then in excess, to a solution of copper(II) sulphate.

Name the gas evolved when dilute hydrochloric acid is added to a carbonate, and state how it is identified.