Among the electrolytes `Na_2SO_4, CaCI_2, AI_2(SO_4)_3` and `NH_4CI` the most effective coagulating agent for `Sb_2S_3` sol is:

Options

A. `Na_(2)S0_(4)`
B. `CaCl_(2)`
C. `AI_(2)(S0_(4))_(3)`
D. `NH_(4)CI`

Answer

C

Explanation

The colloidal particles are coagulated with the addition of electrolytes due to the neutralization of charges. According to Hardy-Schulze rule, larger the charge on the ion, larger its coagulation ability. `Sb_(2)S_(3)` being a negative sol, it will be coagulated most effectively by `AI_(2)(S0_(4))_(3)` as Al3+ ion carries the larger positive charge.