Solveeit Logo
Login

Question

Question: > Mole fraction of A in H2O is 0.2. The molality of A in H2O is :...

Mole fraction of A in H2O is 0.2. The molality of A in H2O is :

A

13.9

B

15.5

C

14.5

D

16.8

Answer

13.9

Explanation

Solution

(1)

Mole fraction of A i.e. XA =nATotalmoles= \frac{nA}{Totalmoles}

So XH2O =nH2OTotalmoles= \frac{nH_{2}O}{Totalmoles}

Now XAXH2O=nAnH2O\frac{X_{A}}{X_{H_{2}O}} = \frac{n_{A}}{n_{H_{2}O}}

and molality =nA×1000nH2O×18=XA×1000XH2O×18=0.2×10000.8×18=13.9= \frac{nA \times 1000}{n_{H_{2}O} \times 18} = \frac{X_{A} \times 1000}{X_{H_{2}O} \times 18} = \frac{0.2 \times 1000}{0.8 \times 18} = 13.9