Question

Molar ratio in a mixture of water and absolute alcohol is 0.2. The mole fraction ratio of alcohol and water is?

Answer 1

The sum of all the mole fractions for the solution = 1

 

mole fraction of A = 0.2

 

so mole fraction H2O = 1 - 0.2 = 0.8

 

 

molality = moles solute / kg solvent

 

 

molar mass H2O = 1.01 * 2 + 16.00 = 18.02 g/mol

 

mass H2O = 0.8 mol H2O x [18.02 g / mol] x [1 kg / 1000 g] = 0.014 kg H2O

 

 

so molality = 0.2 / 0.014 = 14 M(approx

Answer 2

Answer:

5.

Explanation:

as we know that mole ratio of water to alcohol is 0.2

moles of water / moles of alcohol = 0.2/1 = 0.2

we have to find mole fraction of alcohol to water ,

we know the formulae

mole fraction of a A = no of moles of A / no of moles of A + no of moles of B.

mole fraction of alcohol / mole fraction of water = no of moles of alcohol / no of moles of water .

as the bases are same they get cancelled .

= 1/0.2

= 10/2

= 5 .

hope you got this

therefore the final answer is 5 .