Question

The sum of mole fractions of A ,B, C in an aqueous solution containing 0.2 moles of each A, B,C is a) 0.6 b)0.2 c)1.0 d)0.1

Answer 1

mole fraction = moles of each / total moles
 mole fractions of a,b and c = 0.2/0.6 = 1/3
sum of mole fraction of a,b and c is 1/3+1/3+1/3 = 1  (C)

Answer 2

Answer:  c) 1.0

Explanation:-

Mole fraction is the ratio of moles of that component to the total moles of solution.

$\text{Mole fraction of solute}=\frac{\text{Moles of solute}}{\text{Total Moles} }$

$\text{Mole fraction of A}=\frac{\text{Moles of A}}{\text{ Moles of (A+B+C)}}=\frac{0.2}{0.2+0.2+0.2}=0.33$

$\text{Mole fraction of B}=\frac{\text{Moles of B}}{\text{ Moles of (A+B+C)}}=\frac{0.2}{0.2+0.2+0.2}=0.33$

$\text{Mole fraction of C}=\frac{\text{Moles of C}}{\text{ Moles of (A+B+C)}}=\frac{0.2}{0.2+0.2+0.2}=0.33$

The sum of mole fractions of A ,B, C in an aqueous solution containing 0.2 moles of each A, B,C is = 0.33+0.33+0.33= 1.0