Question

The flocculating power of the given ions for the specified colloidal sols will be such that

• A.

  Arsenic sulphoid sol	Ferric hydroxide sol
  $\left(\left[F e \left(C N\right)_{6}\right]\right)^{4 -}>PO_{4}^{3 -}>SO_{4}^{2 -}>Cl^{-}$	$Al^{3 +}>Ba^{2 +}>Na^{+}$

• B.

  Arsenic sulphoid sol	Ferric hydroxide sol
  $Al^{3 +}>Ba^{2 +}>Na^{+}$	$\left(\left[F e \left(C N\right)_{6}\right]\right)^{4 -}>PO_{4}^{3 -}>SO_{4}^{2 -}>Cl^{-}$

• C.

  Arsenic sulphoid sol	Ferric hydroxide sol
  $Na^{+}>Ba^{2 +}>Al^{3 +}$	$Cl^{-}>SO_{4}^{2 -}>PO_{4}^{3 -}>\left(\left[F e \left(C N\right)_{6}\right]\right)^{4 -}$

• D.

  Arsenic sulphoid sol	Ferric hydroxide sol
  $Cl^{-}>SO_{4}^{2 -}>PO_{4}^{3 -}>\left(\left[F e \left(C N\right)_{6}\right]\right)^{4 -}$	$Na^{+}>Ba^{2 +}>Al^{3 +}$

Answer 1

Answer: (B)

Coagulation power depends on nature of charge and amount of charge
Coagulation power $ \propto $ charge on ion of electrolyte
As Arsenic sulphoid sol is negatively charged so for it cations will cause precipitation of ions and the order is $Al^{3 +}>Ba^{2 +}>Na^{+}$
As Ferric hydroxide sol is positively charged so for it anions will cause precipitation of ions and the order is
$\left[ Fe ( CN )_{6}\right]^{4-}> PO _{4}^{3-}> SO _{4}^{2-}> Cl ^{-}$