1.

Find the freezing point of the solution containing 3.6 g of glucose dissolved in 50 g of H2O. (Kf for H2O = 1.86 K/m).

Answer»

Mass of glucose, WB = 3.6 g

Molecular mass of glucose = 180 g mol-1

Mass of solvent, WA = 50 g

Kf for H2O = 1.86 K/m

= 1.86 K kg-1 mol-1

MB\(\frac{1000K_f\,\times\,W_B}{W_A\,\times\,\bigtriangleup T_f}\)

∴ \(\bigtriangleup T_f\) = \(\frac{1000K_f\,\times\,W_B}{W_A\,\times\,M_B}\)

\(\frac{1000\,g\,kg^{-1}\,\times\,1.86\,K\,kg^{-1}\,mol^{-1}\,\times\,3.6\,g}{50\,g\times180\,g\,mol^{-1}}\)

= 0.744 K.

i.e., ΔTf = T°f – Tf

= 0.744 K

∴ Freezing point of the solution,

Tf = T°f – ΔT

= 273 K – 0.744 K

= 272.3 K



Discussion

No Comment Found

Related InterviewSolutions