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Question #44423
The Question
Consider the esterification of the following substituted benzoyl chlorides with excess methanol at 298 K: \begin{enumerate} \item[(I)] 4-Nitrobenzoyl chloride \item[(II)] 3,5-Dinitrobenzoyl chloride \item[(III)] 2-Nitrobenzoyl chloride \item[(IV)] 2,6-Dinitrobenzoyl chloride \end{enumerate} Identify the correct decreasing order of their initial rates of reaction.
Options
- A.
II > I > III > IV
- B.
IV > III > II > I
- C.
IV > II > III > I
- D.
I > II > III > IV
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Exception_Exposure
Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.
Concepts Behind This Question
Esterification Steric Hindrance|Inductive Effect Trends|Electrophilic Substitution Activation/Deactivation
Why This Question Is Tricky
Common Mistakes
Students often strictly follow inductive and mesomeric trends, assuming that more electron-withdrawing groups (EWGs) will continuously increase the electrophilicity of the carbonyl carbon, thereby accelerating nucleophilic acyl substitution.
Based on this purely electronic analysis, they might incorrectly predict IV > III > II > I.
However, they fail to account for the 'Ortho-Effect'.
Extreme steric hindrance at the ortho-position physically blocks the incoming nucleophile (methanol) from attacking the carbonyl carbon.
This steric blockage completely nullifies the electronic acceleration provided by the nitro groups, making the highly hindered 2,6-dinitrobenzoyl chloride react the slowest.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Alcohols, Phenols, and Ethers - Class 12 |
| Concept | Esterification Steric Hindrance |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |