MCQ
Which among the following reactions forms acid anhydricie?
- ✓$R - COOH ($excess$)$ heated in presence of $P _2 O _5$
- B$R - COOH$ treated with $PCl _5$
- C$R - COOH$ treated with $NaHCO _3$ (aq)
- D$R - COOH$ treated with $R ^{\prime}- OH$ and heated