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Choose the correct option.
Which of the following electrolytes is least effective in causing flocculation of positively…
Which of the following electrolytes is least effective in causing flocculation of positively charged ferric hydroxide sol?
- (1)$\text{K}_3[\text{Fe}(\text{CN})_6]$
- (2)$\text{K}_2\text{CrO}_4$
- (3)$\text{K}_4[\text{Fe}(\text{CN})_6]$
- (4)$\text{KBr}$
Answer
Answer
AICorrect option: (4)
Answer: (4) $\mathrm{KBr}$
The sol is positively charged, so flocculation is caused by anions; by the Hardy-Schulze rule, the higher the charge on the anion the more effective it is. $\mathrm{Br^-}$ is monovalent, hence $\mathrm{KBr}$ is least effective.
From ISC 2020 Chemistry Paper 1, question 1(b)(iii).