Question

Mole fraction of ethanol in an aqueous solution is
0.04. Molality of the solution is
(1) 1.11
(2) 2.31
(3) 3.12
(4) 5.01​

Answer 1

Answer:

2) 2.31 mol kg‐¹

Explanation:

Given : mole fraction of solute ( ethanol) = 0.04 and mole fraction of solvent ( water) = 1 - 0.04 = 0.96 .

Answer 2

Given: Mole fraction of ethanol in an aqueous solution is 0.04.

To find: We have to find the molality of the solution.

Solution:

Molality of a solution is defined as the amount of solute dissolved in 1000grm of solvent.

Molality can be given as the ratio of mole fraction of solute to multiple of mole fraction of solvent and molecular weight of solvent. This whole ratio is multipled by 1000.

So, molality is-

$\frac{0.04}{0.96} \times {\frac{1000}{18} }$

=2.31

The molality of the solution is 2.31mol/kg.The correct option is 2.