Test for Aqueous Cations

Cards (8)

  • Cation: Aluminium (Al 3+)
    Aqueous Sodium Hydroxide: White precipitate forms, which is soluble in excess giving a colourless solution.
    Aqueous Ammonia: White precipitate forms, which is insoluble in excess.
  • Cation: Zinc (Zn 2+)
    Aqueous Sodium Hydroxide: White precipitate forms, which is soluble in excess giving a colourless solution.
    Aqueous Ammonia: White precipitate forms, which is soluble in excess giving a colourless solution.
  • Cation: Calcium (Ca 2+)
    Aqueous Sodium Hydroxide: White precipitate forms, which is insoluble in excess
    Aqueous Ammonia: No precipitate or very slight white precipitate. If a slight precipitate forms, It is insoluble in excess.
  • Cation: Chromium (Cr 2+)
    Aqueous Sodium Hydroxide: Green precipitate forms, which is insoluble in excess
    Aqueous Ammonia: Green precipitate forms, which is insoluble in excess
  • Cation: Copper (Cu 2+)
    Aqueous Sodium Hydroxide: Light blue precipitate forms, which is insoluble in excess
    Aqueous Ammonia: Light blue precipitate forms, which is soluble in excess, giving a dark blue solution.
  • Cation: Iron(II) (Fe 2+)
    Aqueous Sodium Hydroxide: Green precipitate forms, which is insoluble in excess. On standing for 5 minutes, the surface turns brown.
    Aqueous Ammonia: Green precipitate forms, which is insoluble in excess. On standing for 5 minutes, the surface turns brown as (Fe 3+) is formed.
  • Cation: Iron(III) (Fe 3+)
    Aqueous Sodium Hydroxide: Red-brown precipitate forms, which is insoluble in excess.
    Aqueous Ammonia: Red-brown precipitate forms, which is insoluble in excess.
  • Cation: Ammonium (NH4+)
    Aqueous Sodium Hydroxide: Ammonia gas produced on warming which turns damp red litmus paper blue.