Question

The molality of aq. solution of urea in which mole
fraction of urea is 0.1, is
41) 6.17 m
(2) 5.24 m
(3) 6.98 m
(4) 5.78 m​

Answer 1

Answer:

option 1 is correct. 6.17m

Explanation:

Mole-fraction of Urea = 0.1

So the Solution contains 0.1- moles of urea dissolved in 0.9- moles of water.

MOLALITY (m) is defined as the number of moles of SOLUTE dissolved in 1000- g of SOLVENT.

Here 1000- g of water = 1000/18= 55.55- moles of water.

So number of moles of urea present in (1000- g ) 55.55- moles of water= 0.1/0.9 x 55.55 = 6.1728- m