Which of the following process is not responsible for the presence of electric charge on the sol particles?

Colloidal particles absorb preferentially positive or negative ions present in the dispersion medium. When two or more ions are present in the dispersion medium, the selective adsorption of ions common to the colloidal particles takes place resulting in the formation of positively charged or negatively charged particles in a colloidal solution. There is no absorption of ionic species and it is not responsible for the presence of electric charge on sol particles. Hence, option D is the answer.