Question

A solution has 46% wt by wt% ethyl alcohol in water .find mole fraction of ethyl alcohol

Answer 1

Answer:

It is 0.5

Explanation:

Here, in 100g solution, there is 46g ethyl alcohol

and now, 100-46= 54g of water

Molar mass of ethyl alcohol (C₂H₅OH) = 46

Molar mass of water (H₂O)= 18

No of moles of solute (ethyl alcohol, since its composition is less, its solute)

= $\frac{46}{46}$ = 1

No of moles of solvent (water, since its composition is more, its solvent)

= $\frac{54}{18}$ = 3

we know that mole fraction= $\frac{Na}{Na+Nb}$

where Na = No. of moles of solute

           Nb= No. of moles of solvent

so, the answer is: $\frac{1}{1+3}$ = $\frac{1}{4}$ = 0.25