50mL of 0 . 2 molal urea solution (density = 1 . 012g mL ^ - 1 at...

Mole of urea $= 0 . 2$

Weight of urea = moles of urea $\times$ molar mass

Weight of urea $= 0 . 2 \times 60 = 12g$

Weight of solvent $= 1000g$

Weight of solution $= 1012g$

Volume of solution $= \dfrac{\text{Weight of solution}}{\text{density of solution}}$

$∴$ Volume of solution $= \dfrac{1012}{1 . 012} = 1000ml$

$∵ 1000ml$ solution contain $0 . 2$ mole

$∴ 50ml$ solution contain $= \dfrac{0 . 2 \times 50}{1000} = 0 . 01$

Mole of urea in other solution $= \dfrac{0 . 06}{60} = 0 . 001$

$∴$ Concentration of solution $= \dfrac{0 . 01 + 0 . 001}{\dfrac{300}{1000}}$

Now, osmotic pressure can be calculated as follows,

$∴ \pi = CRT$

$= 0 . 0366 \times 62 \times 300$

$= 682$