Question

1 mole of methyl alcohol is mixed with 4 moles of ethyl alcohol. The mole fraction of ethyl alcohol is:

• A. 0.2
• B. 0.8
• C. 1
• D. 0.6

Answer 1

The correct option is B 0.8

Mole fraction of ethyl alcohol -

$X_A=\frac{n_A}{n_A+n_B}$

where,

$X_A$ = mole fraction of ethyl alcohol

$n_A$ = no. of moles of ethyl alcohol

$n_B$ = no. of moles of methyl alcohol

$=\frac{4}{4+1}$

$=\frac{4}{5}$

$=0.8$

Hence, option (B) is the correct answer.