Identification of Ions by Chemical and Spectroscopic Means

• Carbonate (CO₃²⁻)


  Add dilute acid. Effervescence, carbon dioxide produced.
• Chloride (Cl⁻)


  Acidify with dilute nitric acid, add aqueous silver nitrate. White ppt.
• Bromide (Br⁻)


  Acidify with dilute nitric acid, add aqueous silver nitrate. Cream ppt.
• Iodide (I⁻)


  Acidify with dilute nitric acid, add aqueous silver nitrate. Yellow ppt.
• Nitrate (NO₃⁻)


  Add aqueous sodium hydroxide, drop in aluminum foil, warm. Ammonia produced.
• Sulfate (SO₄²⁻)


  Acidify, add aqueous barium nitrate. White ppt.
• Sulfite (SO₃²⁻)


  Add dilute hydrochloric acid, warm. Sulfur dioxide produced, test for presence.
• Aluminum (Al³⁺)


  1. Add aqueous sodium hydroxide. White ppt., soluble in excess, colorless solution.

  2. Add aqueous ammonia. White ppt., insoluble in excess.
• Ammonium (NH₄⁺)


  1. Add aqueous sodium hydroxide. Ammonia produced on warming.
• Calcium (Ca²⁺)


  1. Add aqueous sodium hydroxide. White ppt., insoluble in excess.

  2. Add aqueous ammonia. No ppt. or very slightly white ppt.
• Chromium (III) (Cr³⁺)


  1. Add aqueous sodium hydroxide. Green ppt., soluble in excess.

  2. Add aqueous ammonia. Grey-green ppt., insoluble in excess.
• Copper (II) (Cu²⁺)


  1. Add aqueous sodium hydroxide. Light blue ppt., insoluble in excess.

  2. Add aqueous ammonia. Light blue ppt., soluble in excess, giving dark blue solution.
• Iron (II) (Fe²⁺)


  1. Add aqueous sodium hydroxide. Green ppt., insoluble in excess.

  2. Add aqueous ammonia. Green ppt., insoluble in excess.
• Iron (III) (Fe³⁺)


  1. Add aqueous sodium hydroxide. Red-brown ppt., insoluble in excess.

  2. Add aqueous ammonia. Red-brown ppt., insoluble in excess.
• Zinc (Zn²⁺)


  1. Add aqueous sodium hydroxide. White ppt., soluble in excess, colorless solution.

  2. Add aqueous ammonia. White ppt., soluble in excess, colorless solution.
• Ammonia (NH₃)


  Turns damp red litmus paper blue.
• Carbon Dioxide (CO₂)


  Turns limewater milky.
• Chlorine (Cl₂)


  Bleaches damp litmus paper.
• Hydrogen (H₂)


  Lighted splint burns with a 'pop' sound.
• Oxygen (O₂)


  Relights a glowing splint.
• Sulfur Dioxide (SO₂)


  Turns acidified aqueous potassium manganate(VII) from purple to colorless.
• Lithium (Li⁺)


  Red color with flame test.
• Sodium (Na⁺)


  Yellow color with flame test.
• Potassium (K⁺)


  Lilac color with flame test.
• Copper (II) (Cu²⁺)


  Blue-green color with flame test.
• Water (H₂O)


  1. Add anhydrous copper (II) sulfate. Anhydrous copper (II) sulfate turns into hydrated copper (II) sulfate. Color change from white to blue.

  2. Add anhydrous cobalt (II) chloride. Anhydrous cobalt (II) chloride turns into hydrated cobalt (II) chloride. Color change from blue to pink.