$10.2\,g$ ascorbic acid $\Rightarrow 0.058$ moles
$\Delta T _{ f }=\left( x \times 10^{-1}\right)^{\circ} C$
$\Delta T _{ f }= k _{ f } \cdot \text { molality }$
$=3.9 \times \frac{0.058}{150} \times 1000$
$=1.5^{\circ}\,C$
$=15 \times 10^{-1 \circ}\,C$
$\begin{matrix}
O\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}-C-Cl-N{{H}_{3}} \\
\end{matrix}$ $\to $ મધ્યવર્તી $\to $ નીપજ
$A$ શું હશે ?