Question

A solution is prepared by dissolving 1.08 gms of human serum albumin. A protein is obtained from blood plasma in 50 c.c of aqueous solution. The solution has an osmotic pressure of 5.85 mm of Hg at 298 K. What is the molar mass of albumin?

• A. 686.55 g/mole
• B. 68655 g/mole
• C. 34328 g/mole
• D. 343.28 g/mole

Answer 1

Answer: (B)

68655 g/mole

$1atm=760mm$

$5.85mm=7.69\times {10}^{-3}atm$

Now,

$\pi =MRT$

$5\cdot 85mm=\frac{w}{M.wt}\times \frac{1000}{V\left(ml\right)}\times R\times T$

$7.69\times {10}^{-3}=\frac{1.08}{Mol.Wt}\times \frac{1000}{50}\times 0.0821\times 298$

$M.wt=\frac{1.08\times 1000\times 0.0821\times 298}{50\times 7.69\times {10}^{-3}}$

$M.wt=68654.79=68655g/mol$.