b
\({k}_{{f}}=1.86\, {k} \cdot\, {kg} / {mol}\)

\({T}_{{f}}^{\circ}=273\, {k}\)

solvent \(: {H}_{2} {O}(625\, {~g})\)

Solute : \(83\, {~g}\) \({CH}_{2}OH-{CH}_{2}OH \Rightarrow\) Non dissociative

solute

\(\Rightarrow \Delta {T}_{{f}}={k}_{{f}} \times {m}\)

\(\Rightarrow\left({T}_{{f}}^{\circ}-{T}_{{f}}^{1}\right)=1.86 \times \frac{83 / 62}{624 / 1000}\)

\(\Rightarrow 273-{T}_{{f}}^{1}=\frac{1.86 \times 83 \times 1000}{62 \times 625}=\frac{154380}{38750}\)

\(\Rightarrow 273-{T}_{{f}}^{1}=4\)

\(\Rightarrow {T}_{{f}}^{1}=259\,{~K}\)