Among the electrolytes the most effective coagulating agent for
sol is:
Hardy-Schulze Rule: Greater the valence of flocculating ion added, greater is its power to cause coagulation. is negative sol. So, cation with greater valency will have greater power to cause coagulation. Among the given electrolytes,
have the higher valence cation
. Therefore,
has highest coagulation power for
Order of coagulating power of given cations is
Hence option 3 is correct.