The charges on the colloidal CdS sol and TiO2 sol are, respectively
S.No | Positively charged sols | Negatively charged sols |
1 | Hydrated metallic oxides. Eg. Al2O3.xH2O,CrO3.xH2O,Fe2O3.xH2O etc. | Metals Eg. Cu,Ag,Au sols |
2 | Basic dye stuffs.Eg. Methylene blue sol | Metallic sulphides Eg. As2S3,Sb2S3,CdS etc |
3 | Haemoglobin | Acid dye stuffs Eg. Eosin, congo red sols |
4 | Oxides Eg. TiO2 sol |
Sols of starch, gum, gelatin, clay, charcoal etc. |