Question

About $0.5\mathrm{g}$ of soil was taken in a test-tube and to this, $10\mathrm{mL}$ of water was added. The mixture was shaken thoroughly and was allowed to stand in a test tube stand. The mixture was filtered. Which of the following is correct regarding the filtrate?

• A. The filtrate is a suspension
• B. The filtrate is a colloidal solution
• C. The filtrate is a true solution
• D. The filtrate is neither a true solution nor a colloidal solution

Answer 1

The correct option is B

The filtrate is a colloidal solution

Explanation for the correct option:

(B) The filtrate is a colloidal solution: Soil particles are separated by the filter paper to a great extent.

• But some finer, almost invisible particles of soil that can not be separated by the filter paper are dispersed in the filtrate.
• Therefore, the filtrate is a heterogeneous mixture of colloids.
• The size of colloidal particles is ${10}^{-6}-{10}^{-9}\mathrm{m}$

Explanation for the incorrect options:

(A) The filtrate is a suspension: It is not a suspension because suspension contains very large size particles and those are separated by the process of filtration.

• The size of the particles of a suspension is more than${10}^{-6}\mathrm{m}$.

(C) The filtrate is a true solution: It is not a true solution because a true solution is a homogeneous mixture of extremely small particles of solute.

• The size of the particles of solute in a true solution is less than${10}^{-9}\mathrm{m}$.

(D) The filtrate is neither a true solution nor a colloidal solution: It is not correct as filtrate is a colloidal solution.

Hence, option (B) is correct.