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Explain the methods of preparation of colloids of (i) AS_(2)S_(3) (ii) S. |
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Answer» Solution :(i) Double decomposition: When HYDROGEN sulphide gas is passed through a solution of arsenic OXIDE, a yellow coloured arsenic sulphide is obtained as a colloidal solution. `AS_2O_3 +3H_2S to underset("Colloid")(AS_2S_3) + 3H_2O` (ii) Decomposition:- When few drops of an acid is added to a dilute solution of sodium thiosulphate, the insoluble free sulphur produced by the decomposition of sodium thiosulphate accumulates into CLUSTERS which impart various colours blue, yellow and EVEN red to the system depending on their growth within the SIZE of colloidal dimensions. `S_2O_3^(2-) +2H^(+) to underset("sol")(S) + H_2O + SO_2` |
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