Question

To a mixture of sulphur, iron filings, carbon, and potassium chloride taken in a test tube, water was added. The mixture was shaken thoroughly and filtered. The filtrate contains

• A. iron filings
• B. carbon
• C. sulphur
• D. potassium chloride

Answer 1

The correct option is D

potassium chloride

Explanation for the correct option:

(D) potassium chloride: Water is a polar solvent. Potassium chloride $\left(\mathrm{KCl}\right)$ is an ionic compound.

• Potassium chloride dissolves in water and obtained in the filtrate.
• Being a polar compound, water has a slight negative charge on Oxygen $\left(\mathrm{O}\right)$ and a slight positive charge on Hydrogen $\left(\mathrm{H}\right)$.
• In potassium chloride, Potassium $\left({\mathrm{K}}^{+}\right)$ ion has a positive charge and Chlorine $\left({\mathrm{Cl}}^{-}\right)$ has a negative charge.
• The force of attraction develops between the slightly positive charge of water with the negative charge of chloride of potassium chloride and between the slightly negative charge of water with the positive charge of potassium cation of potassium chloride.
• This force of attraction weakens the force of attraction within the potassium chloride ion or ionic bond breaks and potassium chloride dissolves.

Explanation for the incorrect options:

(A) iron filings: Iron $\left(\mathrm{Fe}\right)$ is insoluble in water. Therefore, it is not obtained in the filtrate.

(B) carbon: Carbon $\left(\mathrm{C}\right)$ is also insoluble in water. Therefore, it is not obtained in the filtrate.

(C) sulphur: Sulphur $\left(\mathrm{S}\right)$ is insoluble in water. So, it does not dissolve and not obtained as the filtrate.

Hence, option (D) is correct.