Question

What is the mole fraction of the solute in a $1.0M$ aqueous solution?

• A. $1.770$
• B. $0.0354$
• C. $0.0177$
• D. $0.177$

Answer 1

Answer: (C)

molality $=1$
$x_{\text{solute }}=\frac{\text{ moles of solute }}{n_T}$
$m=\frac{\text{moles of solute}}{\text{mass of solvent }\left(\text{kg}\right)}$
let the mass of solvent $=1kg\left(1000g\right)$
moles of solvent $=\frac{1000}{18}=55.55$
$n_{\text{solute }}=1$
$x_{\text{solute }}=\frac{1}{1+55.55}$
$=.0177$