\(10.2\,g\) ascorbic acid \(\Rightarrow 0.058\) moles
\(\Delta T _{ f }=\left( x \times 10^{-1}\right)^{\circ} C\)
\(\Delta T _{ f }= k _{ f } \cdot \text { molality }\)
\(=3.9 \times \frac{0.058}{150} \times 1000\)
\(=1.5^{\circ}\,C\)
\(=15 \times 10^{-1 \circ}\,C\)
$C{H_3}COOH + PC{l_5} \to A\mathop {\xrightarrow{{{C_6}{H_6}}}}\limits_{anh.\,AlC{l_3}} $ $B\mathop {\xrightarrow{{{C_2}{H_5}MgBr}}}\limits_{ether} C$