Reaction of thionyl chloride with white phosphorus forms a compound [ A ], which on hydrolysis gives [ B ], a dibasic acid. [ A ] and [ B ] are…

Reaction of thionyl chloride with white phosphorus forms a compound $\displaystyle [\mathrm{A}]$, which on hydrolysis gives $\displaystyle [\mathrm{B}]$, a dibasic acid. $\displaystyle [\mathrm{A}]$ and $\displaystyle [\mathrm{B}]$ are respectively