Question

Which of the following electrolytes will have the maximum coagulating value for $Fe _{2} O _{3} \cdot x H _{2} O / OH ^{-}$ sol?

• A. $MgSO _{4}$
• B. $Al _{2}\left( SO _{4}\right)_{3}$
• C. $NaCl$
• D. $BaSO _{4}$

Answer 1

Answer: (B)

$Fe _{2} O _{3} \cdot x H _{2} O / OH ^{-}$sol
Negatively charged colloids
$ MgSO _{4} \longrightarrow Mg ^{2+} $
$ Al _{2}\left( SO _{4}\right)_{3} \longrightarrow Al ^{3+} $
$ NaCl \longrightarrow Na ^{+} $
$ BaSO _{4} \longrightarrow Ba ^{2+}$
Order of coagulation power
$Al ^{3+}> Mg ^{2+}= Ba ^{2+}> Na ^{+}$