Question

Assertion:
An ordinary filter paper impregnated with colloidal solution stops the flow of colloidal particles.
Reason:
Pore size of the filter paper becomes more than the size of colloidal particles.

Answer 1

Hint: The concept of physical chemistry which includes the fact about the ordinary filter paper which has the pore size of lower value and this fact can give the answer relating to that of the size of colloidal particles.

Complete step by step answer:
- In the basic laboratory experiment of inorganic and organic chemistry, we have used the filter paper to separate the minute solid particles from the solution and also have known several facts regarding it.
Let us now see in detail about the pore size of the ordinary filter paper and approach the required answer.
- Filter paper is the semi permeable paper which acts as a barrier and is placed in perpendicular direction to the liquid or the air flow. It is used for the separation of fine solid particles from liquids or gases.
- The pore size of the filter paper varies based on the quality and usually the ordinary filter paper has the pore size of about $11\mu m$.
- The colloid is having two phases namely continuous phase and the dispersed phase and the size of the colloidal particles ranges from $1nm$ to $1\mu m$
- This fact tells that the pore size of the filter paper is larger than the size of the colloidal particles. Thus, the colloidal solution is impregnated on this filter paper so that pore size of the filter paper can be reduced.
Therefore the assertion is true.
- Since the pore size of the ordinary filter paper is large, the colloidal particles pass through this but pore size does not become more than that of colloidal particles.
Thus the reason is incorrect here. The correct option is option “C” .

Note: Do not be confused with ordinary filter paper and Whatman filter paper. The key difference is that ordinary filter paper is used for both quantitative and qualitative analysis and Whatman filter paper is suitable only for qualitative analysis and the pore size of ordinary filter paper is larger than Whatman filter paper.