Question

A solution of sucrose (molar mass $=342$ g/mol) is prepared by dissolving $68.4$ g of it per litre of solution, what is its osmotic pressure at $273$ K?

$[R=0.082L$ atom $K^{-1}mo{l}^{-1}]$

• A. $3.92$ atm
• B. $4.48$ atm
• C. $5.92$ atm
• D. $29.4$ atm

Answer 1

The correct option is B $4.48$ atm

Osmotic pressure, $\pi =$CRT

Here, C$=$ molar concentration of sucrose solution.

$C=\frac{\text{weight (in g) of sucrose}}{\text{molecular weight (in g/mol) of sucrose}\times \text{volume (in L) of solution}}$

$C=\frac{\text{68.4 g}}{\text{342 g/mol}\times \text{1 L}}$
Osmotic pressure,

$\pi =\frac{\text{68.4 g}}{\text{342 g/mol}\times \text{1 L}}\times \text{0.082 L atm / mol /K}\times \text{273 K}$

$\pi =\text{4.48 atm}$.