Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Dissolved substances can be removed from a colloidal solution by diffusion through a parchment paper.
Reason R: Particles in a true solution cannot pass through parchment paper but the colloidal particles can pass through the parchment paper.
In the light of the above statements, choose the correct answer from the options given below:

We need to evaluate the Assertion and Reason about dialysis of colloidal solutions.

Analyzing Assertion A:

Assertion A states that dissolved substances can be removed from a colloidal solution by diffusion through a parchment paper. This is the principle of dialysis. In dialysis, a colloidal solution is placed in a bag made of parchment paper (a semi-permeable membrane). The dissolved ions and molecules (true solution particles) pass through the parchment paper into the outer liquid, while the larger colloidal particles are retained.

$$\therefore$$ Assertion A is correct.

Analyzing Reason R:

Reason R states that particles in a true solution cannot pass through parchment paper but colloidal particles can. This is the opposite of what actually happens:

- True solution particles (ions, small molecules) can pass through parchment paper.

- Colloidal particles are too large and cannot pass through parchment paper.

$$\therefore$$ Reason R is incorrect.

Conclusion:

A is correct but R is not correct.

Hence, the correct answer is Option C.