Question

The osmotic pressure at $17^{\circ }C$ of an aqueous solution containing $1.75g$ of sucrose per $150mL$ solution is :

• A. 0.08 atm
• B. 8.1 atm
• C. 0.8 atm
• D. 9.1 aim

Answer 1

Answer: (C)

Use formula $PV=nRT$ to solve the problem.
$P=$ osmotic pressure $=?$
$V=150mL=0.15L$
$n=$ no. of moles $=\frac{\text{ mass of solute }}{\text{ molecular mass of solute }}$
$=\frac{1.75g}{342}$
$=0.005$
$R=0.0821$
$T=17^{\circ }C=17+273=290K$
$PV=nRT$
or $P=\frac{nRT}{V}$
$=\frac{0.005\times 0.0821\times 290}{0.15}$
$=0.8$ atm