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 ($R = 0.082 \,L$ atom $K^{-1}$ $mol^{-1}$) at $273\, K$?

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

Answer 1

Answer: (B)

Osmotic pressure $(\pi)= CRT$
Here, $C =$ concentration of solution
$C =\frac{ n }{ V }$
$\therefore n =\frac{ w }{ m }=\frac{\text { weight in gram of substance }}{\text { Mol. weight of substance }}$
$V =1$ litre
$C =\frac{68.4}{342}$
$\pi=\frac{68.4}{342} \times 0.082 \times 273$
$=4.48\, atm$