Question

46 gm of ethyl alcohol is dissolved in 18gm of water . Calculate the mole

fraction of ethyl alcohol.
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Answer 1

Given:-

→Mass of ethyl alcohol (solute) = 46g

→Mass of water (solvent) = 18g

To find:-

→Mole fraction of ethyl alcohol

Solution:-

•Chemical formula of ethyl

alcohol = C₂H₅OH

•Chemical formula of water = H₂O

Molar mass of ethyl alcohol :-

= 12×2+1×5+16+1

= 24+5+17

= 46g

Molar mass of water :-

= 1×2+16

= 18g

Number of moles in 46g of ethyl alcohol:-

= Given Mass/Molar mass

= 46/46

= 1 mole

Number of moles in 18g of water:-

= 18/18

= 1 mole

Mole fraction:-

= Moles of solute/Total moles in

solution

= 1+/(1+1)

= 1/2

= 0.5

Thus, the mole fraction of ethyl alcohol is 0.5.