JEE Main 2026 Chemistry question
20 g hemoglobin in a 1 L aqueous solution (A) at 300 K is separated from pure water by semi permeable membrane. At equilibrium the height of solution in a tube dipped in solution (A) is found to be 80.0 mm higher than the tube dipped in water. The molar mass of hemoglobin is kg mol⁻¹. (Nearest integer) (Given: g=10 m/s², R=8.3 kPa dm³ K⁻¹mol⁻¹, density of solution=1000 kg m⁻³)
Answer: 62
Solution
π=ρgh=1000×10×0.08=800 Pa=0.8 kPa. π=(w/M)RT/V: 0.8=(20/M)(8.3)(300)/1, giving M≈62250 g/mol≈62 kg/mol.