Compounds of Tin

Compounds of Tin

Compounds of Tin

  1. Stannous oxide, SnO

    Preparation:

    1. It is prepared by adding sodium hydroxide to stannous chloride. The stannous hydroxide thus formed is heated in an atmosphere of CO2 when SnO is formed.

      SnCl2 + 2NaOH  Sn(OH)2 + 2NaCl

      Sn(OH)2               SnO + H2O

    2. By heating a mixture of solid stannous chloride and sodium carbonate in atmosphere of CO2.

      SnCl2 + Na2CO SnO + CO2 + 2NaCl

    Properties

    1. It is a dark grey powder, which is insoluble in water.

    2. It burns in air forming stannic oxide.

      2SnO + O2  2SnO2

    3.  It is an amphoteric oxide.

      SnO + 2HCl  SnCl2 + H2O



  2. Stannic oxide, SnO2

    Preparation
    :

    1. It is prepared by heating tin in air or by heating metastannic acid.

      Sn + O2  SnO2

      Sn + 4HNO H2SnO+ 4NO2 + H2O

      H2SnO SnO2 + H2O

    Properties:

    1. It dissolves in conc. H2SO4.

      SnO2 + 2H2SO4  Sn (SO4)2 + 2H2O

    2. It readily dissolves in alkalies forming stannates

      SnO+ 2KOH  k2SnO+ H2O
  3. Stannous chloride, SnCl2

    Preparation
    :

    1. Hydrated SnCl2.2H2O is prepared by dissolving tin in hot conc. hydrochloric acid in subjecting the solution to crystallisation.

      Sn +2HCl  SnCl+ H2

    2. Anhydrous stannous chloride is obtained by passing dry HCl gas over hot tin.

      Sn + 2HCl(g)  SnCl+ H2

    Properties:

      1. It is white, crystalline solid, soluble in water and alcohol.

      2. If forms a white precipitate with alkalies. The precipitate however dissolves in excess of alkali.

        SnCl+ 2NaOH  Sn(OH)+ 2NaCl

        Sn (OH)+ 2NaOH  Na2SnO+ 2H2O

      3. It forms dark brown precipitate of stannous sulphide on passing H2S through its solution.

        SnCl+ H2 SnS + 2HCl

        SnS + (NH4)2S2  (NH4)2SnS3

      4. It is a strong reducing agent.

        1. 2HgCl2 + SnCl2  Hg2Cl2 + SnCl4

          Hg2Cl2 + SnCl2  2Hg + SnCl4

        2. 2FeCl3 + SnCl2  2FeCl2 + + SnCl4

        3. SnCl2 2HCl + l2  SnCl4 + 2Hl

        4. 2AuCl3 + 3SnCl2  2Au + 3SnCl4
  4. Stannic Chloride, (SnCl4)

    1. It is prepared by passing dry Cl2 over fused tin in a retort. The vapours of stannic chloride are condensed in water cooled reservoir.
                  Sn + 2Cl2  SnCl4

    Properties:

    1. It is a colourless fuming liquid having disagreeable smell.

    2. It is hydroscopic and forms crystalline hydrates containing 3, 5, 6 and 8 molecules of water as water of crystallisation. The pentahydrate SnCl4.5H2O is known as "butter of tin".

    3. It is soluble in water

      SnCl4 + 4H2 Sn(OH)4 +4HCl

    4. It is dissolves in conc. HCl forming chlorostannic acid.

      SnCl+ 2HCl  H2SnCl6

No ratings yet - be the first to rate this.

Add a comment

You're using an AdBlock like software. Disable it to allow submit.