Compounds of Tin

Compounds of Tin

Compounds of Tin

  1. Stannous oxide, SnO


    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


    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


    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


    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


    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


      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


    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

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