Question

if mole fraction of Naoh in its aqueous solution is 0.2 ,then approximate molality of Naoh solution will be
A.13.9
b.10.9

Answer 1

Definition:

Molality is the moles of solute per Kg of the solvent.

In this case the solvent is water.

Moles in 1000g of water is :

1000 / 18 = 55.6moles

Mole fraction of solute = moles of solute / total moles

Let moles of a NaOH be X then :

X / (X + 55.6) = 0.2

X = 11.12 + 0.2X

0.8 X = 11.12

X = 11.12 / 0.8

X = 13.9

The molality of NaOH is thus 13.9

Answer 2

Answer:

13.9

Explanation: