Question

Which of the following compounds is least effective in precipitating $Fe\left(OH\right)_{3}$ sol.?

• A. $K_{4}\left[Fe\left(CN\right)_{6}\right]$
• B. $K_{2}CrO_{4}$
• C. KBr
• D. $K_{2}SO_{4}$

Answer 1

Answer: (C)

KBr

Answer 2

$Fe\left(OH\right)_{3}$ is positively charged sol. charge of $Br^{-}$ anion is least and so KBr is least effective in coagulating $Fe\left(OH\right)_{3} sol.$