metal hydroxides

• • sodium hydroxide can be used to identify cations
  • many metal hydroxides are insoluble and form white precipates
  • some hydroxides form coloured precipitates
• • calcium forms a white precipitate
• • copper (II) forms a blue precipitate
• • iron(II) forms a green precipitate
  • iron(III) forms a blue precipitate
• • aluminum forms a white precipitate, which dissolves into a colourless soltuion when in excess sodium hydroxide solution