Explain what is observed
(a) When an electrolyte NaCl is added to ferric hydroxide sol.
(b) When an emulsion is subjected to centrifugation.
(c) When direct currect is passed through a colloidal sol.
(d) When a beam of light is passes through a colloidal solution.

Explanation

The positively charged colloidal sol of FeCS get coagulated by the oppositely charged `Cl^(-)` ions provided by NaCl.