Solutions — Easy JEE chemistry MCQ
The osmotic pressure of a solution containing $6$ g of urea (molar mass = $60$ g/mol) in $500$ mL of solution at $27°$C is (R = $0.082$ L·atm/mol·K):
- A. $2.46$ atm
- B. $4.92$ atm
- C. $0.492$ atm
- D. $1.23$ atm
Solution
Osmotic pressure: $\pi = CRT = \frac{n}{V}RT$
Number of moles of urea: $n = \frac{6}{60} = 0.1$ mol
Volume: $V = 500$ mL $= 0.5$ L
Temperature: $T = 27 + 273 = 300$ K
$$\pi = \frac{0.1}{0.5} \times 0.082 \times 300$$
$$\pi = 0.2 \times 0.082 \times 300 = 4.92 \text{ atm}$$