Question:
Which of the following is the most acidic: Ethanol, Phenol, or \(o\)-Nitrophenol?
Which of the following is the most acidic: Ethanol, Phenol, or \(o\)-Nitrophenol?
Show Hint
Electron-withdrawing groups such as \(NO_2\) increase acidity by stabilizing the conjugate base through inductive and resonance effects.
Updated On: Apr 30, 2026
- Ethanol
- Phenol
- \(o\)-Nitrophenol
- All have same acidity
Show Solution
Verified By Collegedunia
The Correct Option is C
Solution and Explanation
Concept:
Acidity depends on the stability of the conjugate base formed after the loss of a proton.
Electron-withdrawing groups increase acidity by stabilizing the negative charge through inductive (\(-I\)) and resonance (\(-M\)) effects.
Step 1: Compare ethanol and phenol. Phenol is more acidic than ethanol because the phenoxide ion formed after deprotonation is stabilized by resonance over the benzene ring, whereas ethanol does not have such stabilization.
Step 2: Effect of the nitro group in \(o\)-Nitrophenol. The nitro group \((NO_2)\) is a strong electron-withdrawing group. It stabilizes the phenoxide ion through both: \[ -I \text{ effect (inductive)} \] \[ -M \text{ effect (resonance)} \] This withdrawal of electron density from the \(O-H\) bond increases the tendency to lose \(H^+\).
Step 3: Conclusion. Because of the strong electron-withdrawing nitro group, \(o\)-Nitrophenol is more acidic than both phenol and ethanol.
Step 1: Compare ethanol and phenol. Phenol is more acidic than ethanol because the phenoxide ion formed after deprotonation is stabilized by resonance over the benzene ring, whereas ethanol does not have such stabilization.
Step 2: Effect of the nitro group in \(o\)-Nitrophenol. The nitro group \((NO_2)\) is a strong electron-withdrawing group. It stabilizes the phenoxide ion through both: \[ -I \text{ effect (inductive)} \] \[ -M \text{ effect (resonance)} \] This withdrawal of electron density from the \(O-H\) bond increases the tendency to lose \(H^+\).
Step 3: Conclusion. Because of the strong electron-withdrawing nitro group, \(o\)-Nitrophenol is more acidic than both phenol and ethanol.
Was this answer helpful?
1
0
Top VITEEE Chemistry Questions
- Which of the following is not a characteristic of transition elements ?
- Most crystals show good cleavage because their atoms, ions or molecules are
- Which of the following sets consists only of essential amino acids ?
- The chemical composition of slag formed during the smelting process in the extraction of copper is
- The reaction,Zn(s) + CuSO4(aq) $\rightarrow$ZnSO4(aq) + Cu(s) is an example of a
View More Questions
Top VITEEE Alcohols, Phenols and Ethers Questions
- What are $X$ and $Y$ in the following reaction sequence $C _{2} H _{5} OH \ce{->[{ Cl _{2} }]} \underline{X} \ce{->[{ Cl _{2}}]}\underline{Y}$
- When aqueous solution of benzene diazoniumchloride is boiled, the product formed is
- \({A->[K_2Cr_2O_7][dil.H_2SO_4]B->[CH_3MgI][H_2O]CH3}\) the reactant A is
- Phenol undergoes electrophilic substitution more easily than benzene because
- Ethylene glycol, on oxidation with periodic acid, gives:
View More Questions
Top VITEEE Questions
- A motor of power $P_0$ is used to deliver water at a certain rate through a given horizontal pipe. To increase the rate of flow of water through the same pipe $n$ times, the power of the motor is increased to $P_1$. The ratio of $P_1 $ to $P_0$ is
- A $30\,V-90\,W$ lamp is operated on a $120\,V$ DC line. A resistor is connected in series with the lamp in order to glow it properly. The value of resistance is
- Which of the following is not a characteristic of transition elements ?
- Most crystals show good cleavage because their atoms, ions or molecules are
- Which of the following sets consists only of essential amino acids ?
View More Questions