Arsenic sulphide sol is prepared by passing H2S in As2O3
Preparation of Arsenious Sulphide sol
Arsenious sulphide is a lyophobic colloid. It is formed due to the hydrolysis of As2O3 (Arsenious oxide) in boiled distilled water. Further H2S gas is passed through the solution. The reaction is as follows,
As2O3 + 3H2O → 2As(OH)3
2As(OH)3 + 3H2S → As2S3 + 6H2O
The particles in Arsenious sulphide colloidal solution are surrounded by HS ions which are formed due to the dissociation of H2S. The Sulphide ion layer is surrounded by H+ ions.