Question

If the mole fraction of a solute in a binary solution is $0.3$, what could be the mole fraction of the solvent in the solution? If answer is $x$, then write it as $10x$.

• A. 8
• B. 7
• C. 0.7
• D. 9

Answer 1

The correct option is B 7

Mole fraction (x) : The ratio of number of moles of the solute or solvent present in the solution and the total number of moles present in the solution is known as the mole fraction of sub-stances concerned.
Mole fraction $=\frac{\text{No. of moles of a Substance}}{\text{Total number of moles of all substances in the mixture}}$
Also,
$X_A+X_B=1$
Sum of the mole fractions in a mixture $=$ 1
So, mole fraction of the solvent $1-0.3=0.7$