Among the electrolytes Na₂SO₄, CaCl₂, Al₂(SO₄)₃ and NH₄Cl, the most effective coagulating agent for — Surface Chemistry Chemistry Question

💡 Solution & Explanation

Sb₂S₃ is a negatively charged sulphide sol. According to the Hardy-Schulze rule, an electrolyte providing a cation with a higher positive charge will be more effective. Al³⁺ (from Al₂(SO₄)₃) has the highest valency (+3). Therefore, correct answer is C.