Question

A solution is made by dissolving 20 g of substance in 500 mL of water. Its osmotic pressure was found to be 600 mm of Hg at $15ºC$. Find the molecular weight of the substance.

• A. 1198
• B. 500
• C. 1200
• D. 1000

Answer 1

Answer: (A)

1198

Answer 2

$M = \frac{W_{B}RT}{\pi V} = \frac{20 \times 0.0821 \times 288 \times 1000}{(600/760) \times 500} = 1198$