Question

138 g ethyl alcohol is mixed with 72 g of water. The ratio of mole fraction of alcohol to water is ______.

विकल्प

• 3 : 4

• 1 : 2

• 1 : 4

• 1 : 1

Answer 1

138 g ethyl alcohol is mixed with 72 g of water. The ratio of mole fraction of alcohol to water is 3 : 4.

Explanation:

Molecular mass of ethyl alcohol = 46 g/mol

Molecular mass of water = 18 g/mol

Number of moles of C₂H₅OH = `138/46` = 3

Number of moles of H₂O = `72/18` = 4

Mole fraction, `chi_("C"_2"H"_5"OH") = 3/(3 + 4) = 3/7`

`chi_("H"_2"O") = 4/(3 + 4) = 4/7`

`chi_("C"_2"H"_5"OH")/chi_("H"_2"O") = (3/7)/(4/7) = 3/4 => 3 : 4`