MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

Acid strength is directly proportional to the stability of the conjugate base formed after the removal of an H^+ ion. The conjugate bases are: a) Ethoxide ion (CH_3CH_2O^-) b) tert-Butoxide ion ((CH_3)_3CO^-) c) Phenoxide ion (C_6H_5O^-) d) p-Nitrophenoxide ion (p-NO_2-C_6H_4O^-) Phenoxide ions are resonance stabilized, making phenols more acidic than aliphatic alcohols. Thus, (c) and (d) are more acidic than (a) and (b). In p-nitrophenol (d), the -NO_2 group exerts strong -I and -R effects, which further stabilizes the phenoxide ion. Hence, p-nitrophenol is more acidic than phenol (c). Among the alcohols, the +I effect of the alkyl groups destabilizes the alkoxide ion. The tert-butyl group in 2-methylpropan-2-ol (b) exerts a stronger +I effect than the ethyl group in ethanol (a). Therefore, ethanol is more acidic than 2-methylpropan-2-ol. The correct decreasing order of acid strength is d > c > a > b. Answer: d > c > a > b