Question

An aqueous solution of a weak monobasic acid containing $0.1\, g$ in $21.7\, g$ of water freezes at $272.813\, K$. If the value of $K_{f}$ for water is $1.86\, K/m$, what is the molecular mass of the monobasic acid

• A. 50 g/mol
• B. 46 g/mol
• C. 55 g/mol
• D. 60 g/mol

Answer 1

Answer: (D)

$m=\frac{K_{f} \times w\times1000}{\Delta T_{f} \times W}$
$=60 \,g /mole$