cation test metals with NaOH

lots of metal hydroxides and precipitate out of solution as a specific colour ,what test can we do to identify which metal ion it is ( a cation positive)

add sodium hydroxide

Ionic equation for aluminium precipitate formation

Al³⁺(aq) + 3OH⁻(aq) → Al(OH)₃(s)

Ionic equation for calcium precipitate formation

Calcium: Ca²⁺(aq) + 2OH⁻(aq) → Ca(OH)₂(s)

Ionic equation for magnesium percipitate formation

Magnesium: Mg²⁺(aq) + 2OH⁻(aq) → Mg(OH)₂(s)

Ionic equation for copper precipitate formation

Copper(II): Cu²⁺(aq) + 2OH⁻(aq) → Cu(OH)₂(s)

Ionic equation for iron 2 precipitate formation

Iron(II): Fe²⁺(aq) + 2OH⁻(aq) → Fe(OH)₂(s)

Ionic equation for iron 3 precipitate formation

Iron(III): Fe³⁺(aq) + 3OH⁻(aq) → Fe(OH)₃(s)

colour of calcium

white

colour of copper

blue

colour of iron 2

green

colour of iron 3

brown

colour of magnesium

white

colour of aluminium

white first but redissolves in excess NaOH to form colourless solution