Which of the following salt solutions would coagulate the colloid...

Which of the following salt solutions would coagulate the colloid soloution formed when

{FeCl}_{3}

is added to

NaOH

solution, at the fastest rate?

Options

A $10mL$ of $0 . 2mol{dm}^{- 3}{AlCl}_{3}$
B $10mL$ of $0 . 1mol{dm}^{- 3}{Na}_{2}{SO}_{4}$
C10mL $of$ 0 . 1mol{dm}^{- 3}{Ca}_{3}{ $\left({PO}_{4}\right)}_{2}$
D $10mL$ of $0 . 15mol{dm}^{- 3}{CaCl}_{2}$

Correct answer

A. $10mL$ of $0 . 2mol{dm}^{- 3}{AlCl}_{3}$

Step-by-step solution

Generally, the greater the valence of the flocculating ion added, the greater its power to cause precipitation. In the coagulation of a negative sol, the flocculating power is in the order:

${Al}^{3 +} > {Ba}^{2 +} > {Na}^{+}$

${FeCl}_{3}$ with $NaOH$ forms a negative sol.

So, ${AlCl}_{3}$ coagulate it most.

Practice Surface Chemistry on Quantrex Academy →

More from Surface Chemistry

At a given temperature, 0.45 g of acetic acid in 50 mL of water is shaken with 1.0 g of… JEE Advanced 2026 Adsorption of phenol from its aqueous solution on to fly ash obeys Freundlich isotherm.… JEE Advanced 2025 Consider the following statements related to colloids. (I) Lyophobic colloids are not… JEE Advanced 2023 20mL of 0 . 5MNaCl is required to coagulate 200mL of As _ 2 S _ 3 solution in 2 hours.… JEE Main 2023 Given below are two statements, one is labelled as Assertion A and the other is labelled… JEE Main 2023 What happens when a lyophilic sol is added to a lyophobic sol? JEE Main 2023 Four gases, A, B, C and D have critical temperatures 5 . 3, 33 . 2, 126 . 0 and 154 . 3K… JEE Main 2023 The number of correct statements about modern adsorption theory of heterogeneous… JEE Main 2023 Full Surface Chemistry list All JEE Main PYQs