Question

Which of the following electrolytes is least effective in causing flocculation of ferric hydroxide sol?

Options

• K₃Fe(CN)₆

• K₂CrO₄

• KBr

• K₂SO₄

Answer 1

KBr

Explanation:

KBr is the least effective in causing the flocculation of ferric hydroxide sol because it has a monovalent ion (Br⁻), which has a much lower coagulating power compared to the multivalent ions present in other electrolytes like K₃Fe(CN)₆, K₂CrO₄, and K₂SO₄ that have higher charges and thus stronger flocculating abilities for the positively charged ferric hydroxide sol.

Hence, KBr is the least effective in causing flocculation.