Question

In coagulation of positively charged ferric hydroxide sol, the most and least effective ions are ____________ and ____________ respectively.

Options

• `"SO"_4^(2-)`, `"PO"_4^(3-)`

• `"PO"_4^(3-)`, `"NO"_3^-`

• `"NO"_3^-`, `"SO"_4^(2-)`

• `"NO"_3^-`, `"PO"_4^(3-)`

Answer 1

In coagulation of positively charged ferric hydroxide sol, the most and least effective ions are `underline("PO"_4^(3-))` and `underline("NO"_3^-)` respectively.

Explanation:

Hardy-Schulze laws state that ions with opposite charges to sol particles promote coagulation, and the higher the valence of the oppositely charged ion, the stronger the coagulating power, i.e., \[\ce{PO^{3-}_4 > SO^{2-}_4 > NO^-_3}\].