JEE Main202330 Jan 2023Evening ShiftChemistryGeneral Organic ChemistryActual
The correct order of pK a values for the following compounds is:
Options
- Ac > a > d > b
- Bb > d > a > c
- Cb > a > d > c
- Da > b > c > d
Correct answer
B. b > d > a > c
Step-by-step solution
Electron-withdrawing groups increase the acidic nature of the phenol. Nitro group is electron withdrawing group, hence it is the more acidic compound among the given phenols. Electron-donating groups decrease the acidic nature where methoxy group is more electron donating, hence less acidic than the iso-propyl group which donates electrons by hyperconjugation effect. ∴ Order of acidic strength is (c) > (a) > (d) > (b) The order of pK a values are (b) > (d) >(a) > (c).