Question

The osmotic pressure of solution containing $34.2 \,g$ of cane sugar (molar mass = $342 \, g \, mol^{-1}$) in 1L of solution at $20^{\circ} C$ is (Given, $R = 0.082 \, L \, atm \, K^{-1} \, mol^{-1}$)

• A. $2.40\, atm$
• B. $3.6\, atm$
• C. $24\, atm$
• D. $0.0024\, atm$

Answer 1

Answer: (A)

$2.40\, atm$

Answer 2

The expression for the osmotic pressure of the solution is shown below.
$\pi= CRT =\frac{ W }{ M \times V } RT$
Here, $\pi$ is the osmotic pressure,
$C$ is the molar concentration,
$W$ is mass of solute,
$M$ is the molar mass of solute,
$V$ is the volume of the solution in liter,
$R$ is the ideal gas constant and
$T$ is the absolute temperature.
$\pi=\frac{34.2 \,g }{342\, g / mol } \times 0.082\, L \,atm / mol \,K \times 293 \,K$
$\pi=2.40 \,atm$
The osmotic pressure of the solution is $2.40$ atm.