Which of the following arrangements with respect to their reactivity in nucleophilic addition reaction is correct?

### Core Logic Reactivity in nucleophilic addition reactions is governed by a combination of **steric hindrance** and **electronic effects** around the electrophilic carbonyl carbon: 1. Ketones are significantly less reactive than aldehydes due to the bulkiness and electron-donating inductive effect (+I$+I$) of their two alkyl/aryl groups. Thus, **acetophenone** has the lowest reactivity. 2. For substituted benzaldehydes, electron-withdrawing groups heighten the partial positive charge on the carbonyl carbon, accelerating nucleophilic attack. Conversely, electron-donating groups suppress reactivity. Symmetry breakdown structures are shown below: - Acetophenone:

- p-tolualdehyde:

- Benzaldehyde:

- p-nitrobenzaldehyde:

- Methoxy/methyl donors decrease reactivity: textp-tolualdehyde < textbenzaldehyde$\text{p-tolualdehyde} < \text{benzaldehyde}$ - Nitro group (-mathrmNO_2$-\mathrm{NO}_2$) acts as a strong electron-withdrawing agent via both -M$-M$ and -I$-I$ pathways, maximizing the electrophilic nature of the carbonyl site. Therefore, **p-nitrobenzaldehyde** is the most reactive. Thus, the correct order of reactivity is: textacetophenone < textp-tolualdehyde < textbenzaldehyde < textp-nitrobenzaldehyde$$\text{acetophenone} < \text{p-tolualdehyde} < \text{benzaldehyde} < \text{p-nitrobenzaldehyde}$$ ### Pattern Recognition Aldehydes naturally exhibit higher reactivity than ketones. Electron-withdrawing groups (-mathrmNO_2$-\mathrm{NO}_2$) accelerate addition pathways, whereas electron-donating groups (-mathrmCH_3$-\mathrm{CH}_3$) impede them. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Aldehydes, Ketones and Carboxylic Acids