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Question:

At room temperature, a dilute solution of urea is prepared by dissolving 0.60g of urea in 360g of water. If the vapour pressure of pure water at this temperature is 35 mmHg, lowering of vapour pressure will be: (molar mass of urea=60 gmol⁻¹)

0.027mmHg

0.017mmHg

0.031mmHg

0.028mmHg

Solution:

Solution:- (C)0.017mmHg
Lowering of vapour pressure=P₀−p=p₀.x solute
∴ΔP=35 × 0.6/60
0.6/60 + 360/18
=35 × 0.01
0.01 + 20
=35 × 0.01
20.01
=0.17 mmHg