Place the following acid chlorides in the decreasing order of reactivity to hydrolysis. (1) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COCl}\) (2) \(\mathrm{p}-\mathrm{O}_{2} \mathrm{NC}_{6} \mathrm{H}_{4} \mathrm{COCl}\) (3) \(\mathrm{p}-\mathrm{CH}_{3} \mathrm{OC}_{6} \mathrm{H}_{4} \mathrm{COCl}\) (a) \(2>1>3\) (b) \(3>1>2\) (c) \(1>2>3\) (d) \(1>3>2\)

The process of hydrolysis is crucial in understanding the behavior of acyl chlorides in organic reactions. Hydrolysis is the chemical breakdown of a compound due to reaction with water. When it comes to acyl chlorides, also known as acid chlorides, they are highly reactive in the presence of water, forming carboxylic acids and hydrogen chloride gas. This reaction is represented by the general equation:

\[ RCOCl + H_2O \rightarrow RCOOH + HCl \]
where R represents a hydrocarbon group. Acyl chlorides are known for their susceptibility to hydrolysis because the carbonyl carbon (C=O) is attached to a chlorine atom, which is a good leaving group. This leaves a partial positive charge on the carbon, making it highly electrophilic and, as a result, more reactive towards nucleophiles such as water. To understand this concept fully, it's essential to analyze the different electronic effects that substituents could have on this reactivity.

The reactivity of acyl chlorides towards hydrolysis can be directly influenced by different electronic effects exerted by the substituents attached to the aromatic ring. Two main effects come into play: inductive effects and resonance effects.

• Inductive Effects: Electron-withdrawing groups (EWGs) that are connected to the benzene ring can increase the electrophilicity of the carbonyl carbon by pulling electron density away through the sigma bonds. This makes the carbonyl carbon even more susceptible to attack by nucleophiles like water. Conversely, electron-donating groups (EDGs) push electron density towards the carbonyl carbon, reducing its electrophilicity and thus its reactivity to hydrolysis.
• Resonance Effects: Some groups can engage in resonance with the carbonyl group, either withdrawing or donating electron density through the pi system of the aromatic ring, which can impact the carbonyl carbon's reactivity.

Applying these electronic effects in ranking the reactivity of given acyl chlorides yields a clear trend. Compounds with strong EWGs, like a nitro group, significantly enhance the reactivity, while EDGs, such as a methoxy group, decrease the reactivity. Students preparing for exams like NEET must grasp these concepts thoroughly to predict and understand the outcomes of organic reactions.

For students preparing for competitive exams like NEET (National Eligibility cum Entrance Test), understanding the reactivity of organic compounds such as acyl chlorides is vital. Not only does it pertain to proficiency in organic chemistry basics, but it also empowers students to make predictions about reaction outcomes and mechanisms logically.

Organic chemistry questions in NEET often involve analyzing reaction sequences, understanding the influence of structural factors on reactivity, and applying electronic effects. The knowledge of such electronic effects is not just limited to hydrolysis reactions but extends to various other organic transformations—making it a cornerstone concept. For instance, in our exercise, knowing the inductive and resonance effects allows us to correctly rank the acid chlorides in decreasing order of reactivity to hydrolysis. Students are advised to approach such problems by careful analysis of molecular structure, focusing on the presence and nature of substituents, and recalling the underlying principles that govern chemical reactivity. Practice problems similar to ranking the reactivity of acid chlorides are invaluable for honing problem-solving skills crucial for exams like NEET.