Question

Calculate the osmotiic pressure of3,% urea solution at 30%

Answer 1

we know, osmotic pressure,

π = CRT

where i denotes van't - hoff factor and it equals 1 for non- electrolyte substance.

so, i = 1

C denotes concentration of substance.

given, 3% urea solution.

3% urea solution means 3g urea is present in 100ml of solution.

so, number of mole of urea = 3g/60g = 1/20 [ mol wt of urea = 60 g/mol ]

so, molarity = number of mole × 1000/volume of solution

= (1/20) × 1000/100 = 1/2 = 0.5

R denotes universal gas constant so, R = 0.0821 atm.L/K/mol and T denotes temperature in Kelvin.

here, T = 30°C = 273 + 30 = 303K

so, π = 1 × 0.5 × 0.0821 × 303 = 12.43815 atm