NEET2010ChemistryGeneral Organic ChemistryActual
Among the following four compounds A. Phenol B. Methyl phenol C. meta-nitrophenol D. para nitrophenol the acidity order is
Options
- AD > C > A > B
- BC > D > A > B
- CA > D > C > B
- DB > A > C > D
Correct answer
A. D > C > A > B
Step-by-step solution
An electron withdrawing group (-I showing group like .- NO ₂,- CN ) stabilises the phenoxide ion, thus when present, increases the acidity of phenol. On the other hand electron releasing groups ( +I showing group like - CH ₃,- C ₂ H ₅ ), when present, decrease the acidity of phenol by destabilising phenoxide ion. Hence, the correct order of acidity of given compounds is ( (D) p-nitrophenol > (C) m-nitrophenol > (A) phenol > (B) methyl phenol ) (due to intermolecular H -bonding)