Question

The mole fraction of ethanol in water is $0.08$. Its molality is

• A. $6.32molk{g}^{-1}$
• B. $4.83molk{g}^{-1}$
• C. $3.82molk{g}^{-1}$
• D. $2.84molk{g}^{-1}$

Answer 1

Answer: (B)

Molality $=\frac{X_{EtOH}}{X_{H_{2}O}}\times \frac{1000}{M{W}_{\text{solvent }}}$
$=\frac{0.08}{0.92}\times \frac{1000}{18}$
$=4.83molk{g}^{-1}$