A solution has been prepared by dissolved 60 g of methyl alcohol in 120 g of water. What is the mole fraction of methyl alcohol and water ?

Answer

(i) 0.220 (ii) 0.780

Explanation

Moles of `CH_(3)OH=("Mass of "CH_(3)OH)/("Molar mass")=((60 g)/("32 g mol"^(-1)))=1.875` mol
Moles of water `= ("Mass of water")/("Molar mass")=((120g)/("18 g mol"^(-1)))=6.667` mol
Mole fraction of `CH_(3)OH=(("1.875 mol"))/(("1.875 mol +6.667 mol"))=(("1.875 mol"))/(("8.542 mol"))=0.220`
Mole fraction water `= 1 - 0.220 = 0.780`.