Question

138 grams of ethyl alcohol is mixed with 72
grams of water. The ratio of mole fraction of
alcohol to water is
A
3 4
B
1:4
D
11​

Answer 1

Answer:

3:4

Explanation:

Ethyl alcohol = C2H5OH, Mol wt. = 46 g/mol

So, 46 g/mol = 1 mole

138 grams = 138/46 = 3 moles

Water = H2O, Mol wt = 18 g/mol

So, 18 g/mol = 1 mole

72 grams = 72/18 = 4 moles

Therefore, mole fraction of ethyl alcohol

= No. of moles of ethyl alcohol/total no. of moles

= 3/(3+4) = 3/7

And, mole fraction of water = No. of moles of water/total no. of moles

= 4/(3+4) = 4/7

therefore,the ratio of mole fraction of alcohol to water= 3/7 ÷ 4/7

= 3:4

:))