Question

The mole fraction of water in 20% aqueous solution (By
weight) of H₂O₂ is
(a) 77/68 (b) 68/77 (c) 20/80 (d)80/20

Answer 1

The mole fraction of water in 20% aqueous solution of H₂O₂ is $=\frac{68}{77}$

Explanation:

Atomic mass of H₂O= 18 gram/mol

Atomic mass of H₂O₂=(2×1)+(16×2)  = 34 gram/mol

Given, 20% aqueous solution of H₂O₂.

No. of moles of H₂O is $=\frac{80}{18}$

No. of moles of H₂O₂ is$=\frac{20}{34}$

$\textrm{mole fraction of water}=\frac{\textrm{moles of water}}{\textrm{moles of }H_2 O+\textrm{moles of }H_2O_2}}$

                                  $=\frac{\frac{80}{18}}{\frac{80}{18}+\frac{20}{34}}$

                                   $=\frac{68}{77}$

Answer 2

The mole fraction of water in 20% aqueous solution (By

weight) of H₂O₂ is

(a) 77/68

(b) 68/77 ✔✔

(c) 20/80

(d)80/20