Question

Which of the following substances, when mixed with water, do not leave a residue when passed through a filter paper?

• A. Salt
• B. Sand
• C. Corn flour
• D. Chalk powder

Answer 1

The correct option is A Salt

$\bullet$ Filtration is used for separating insoluble solids from a liquid. A filter paper is used to carry out filtration. The filter paper lets the liquid go off while stopping the insoluble solid from passing through.

$\bullet$ Salt dissolves in water and hence, cannot be separated using filter paper.

$\bullet$ However, sand, corn flour and chalk powder are insoluble in water. So, a mixture of these substances with water leaves a residue when passed through a filter paper.