Mr Cole Chemistry

Reactions of Aqueous Aluminium Ions

  • Questions
  • Answers
  1. For the following reactants, write the ionic equation for the for the reaction and state what you would observe during the reaction.
    1. Aluminium nitrate and limited sodium hydroxide.
    2. Aluminium sulfate and hydrochloric acid.
    3. Aluminium nitrate and excess sodium hydroxide.
    4. Aluminium hydroxide and excess sodium hydroxide.
    5. Aluminium nitrate and ammonia.
    6. Aluminium sulfate and sodium carbonate.
    7. Aluminium hydroxide and sulfuric acid.
  2. The following colour changes occurred. Suggest the equation for the reaction that occurred.
    1. A colourless solution –> a white precipitate.
    2. A white precipitate –> a colourless solution.
    3. A colourless solution –> a white precipitate; bubbles given off.
  1. For the following reactants, write the ionic equation for the for the reaction and state what you would observe during the reaction.
    1. Aluminium nitrate and limited sodium hydroxide.
      [Al(H2O)6]3+ + 3OH– –> Al(H2O)3(OH)3 + 3H2O
      Colourless solution –> white precipitate
    2. Aluminium sulfate and hydrochloric acid.
      [Al(H2O)6]3+ + 4Cl– –> [AlCl4]– + 6H2O
      Colourless solution –> colourless solution (no colour change)
    3. Aluminium nitrate and excess sodium hydroxide.
      [Al(H2O)6]3+ + 4OH– –> [Al(H2O)2(OH)4]– + 4H2O
      Colourless solution –> colourless solution (no colour change). You might see a temporary formation of a white precipitate.
    4. Aluminium hydroxide and excess sodium hydroxide.
      Al(H2O)3(OH)3 + OH– –> [Al(H2O)2(OH)4]– + H2O
      White precipitate –> colourless solution
    5. Aluminium nitrate and ammonia.
      [Al(H2O)6]3+ + 3NH3 –> Al(H2O)3(OH)3 + 3 NH4+
      Colourless solution à white precipitate
    6. Aluminium sulfate and sodium carbonate.
      2[Al(H2O)6]3+ + 3CO32- –> 2Al(H2O)3(OH)3+ 3H2O + 3CO2
      Colourless solution –> white precipitate. Bubbles given off.
    7. Aluminium hydroxide and sulfuric acid.
      Al(H2O)3(OH)3 + 3H+ –> [Al(H2O)6]3+
      White precipitate –> colourless solution
  2. The following colour changes occurred. Suggest the equation for the reaction that occurred.
    1. A colourless solution –> a white precipitate.
      [Al(H2O)6]3+ + 3OH– –> Al(H2O)3(OH)3 + 3H2O
      [Al(H2O)6]3+ + 3OH– –> Al(H2O)3(OH)3 + 3H2O
    2. A white precipitate –> a colourless solution.
      Al(H2O)3(OH)3 + OH– –> [Al(H2O)2(OH)4]– + H2O
      Al(H2O)3(OH)3 + 3H+ –> [Al(H2O)6]3+
    3. A colourless solution –> a white precipitate; bubbles given off.
      2[Al(H2O)6]3+ + 3CO32- –> 2Al(H2O)3(OH)3+ 3H2O + 3CO2
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