Question

The osmotic pressure of a solution can be increased by :

• A. Increasing the number of solutes
• B. Increasing the volume
• C. Removing semi-permeable membrane
• D. Decreasing the temperature

Answer 1

The correct option is A

Increasing the number of solutes

Explanation for correct option:

(A) Increasing the number of solutes:

• Osmotic pressure is the lowest pressure that inhibits the inward flow of a pure solvent into a solution that is separated from it by a semipermeable membrane.
• The quantity of solute particles affects osmotic pressure. It varies in proportion to the solution's molarity. So, this is the correct option.

$\mathrm{\pi }=\mathrm{iMRT}$

Where,

$$\begin{gathered} \mathrm{\pi }-\mathrm{osmotic}\mathrm{pressure} \\ \mathrm{M}-\mathrm{Molar}\mathrm{concentration}\mathrm{of}\mathrm{solution} \\ \mathrm{R}-\mathrm{Ideal}\mathrm{gas}\mathrm{constant} \\ \mathrm{T}-\mathrm{temperature} \end{gathered}$$

Explanation for incorrect options:

(B) Increasing the volume :

• According to the formula, there is no effect on the osmotic pressure if the volume increases.

(C) Removing semi-permeable membrane:

• There will be no effect on osmotic pressure on removing the semi-permeable membrane.

(D) Decreasing the temperature

• On decreasing the temperature, the osmotic pressure also decreases.

Hence, the correct option is (A) Increasing the number of solutes will increase the osmotic pressure.