Arrange in decreasing order of acidity: 4-nitrophenol, phenol, 4-methylphenol, cyclohexanol.

Aphenol $>$ 4-nitrophenol $>$ 4-methylphenol $>$ cyclohexanol
B4-nitrophenol $>$ phenol $>$ cyclohexanol $>$ 4-methylphenol
C4-nitrophenol $>$ phenol $>$ 4-methylphenol $>$ cyclohexanol
D4-nitrophenol $>$ 4-methylphenol $>$ phenol $>$ cyclohexanol

Answer: C

The para nitro group withdraws electrons by

- R

and

- I

effects and stabilises the phenoxide ion, so 4-nitrophenol is the strongest acid. The electron-releasing methyl group destabilises the phenoxide, making 4-methylphenol weaker than phenol. Cyclohexanol, an alcohol with no resonance stabilisation of its anion, is the weakest.

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Arrange in decreasing order of acidity: 4-nitrophenol, phenol, 4-methylphenol, cyclohexanol.

Answer: C

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