Match the following question

Answer

A-r, B-s, C-q, D-p

Explanation

B) `R-COOR.` (ester) are fruit flavor
C) HCOOH reduces `HgCl_2` to `Hg_2 Cl_2` which change to mercury black
D) `R-overset(O)overset(||)C-Cl` shows more reactive towards acyl substitution due to good leaning group of `Cl^-`