The correct reactivity order with the nucleophile is :

Options

A. `CH_(3)COClgtCH_(3)CONH_(2)gtCH_(3)COOCH_(3)`
B. `CH_(3)COClgtCH_(3)COOCH_(3)gtCH_(3)COONH_(2)`
C. `CH_(3)CONH_(2)gtCH_(3)COOCH_(3)gtCH_(3)COCl`
D. `CH_(3)COOCH_(3)gtCH_(3)COClgtCH_(3)CONH_(2)`

Answer

To determine the correct reactivity order of nucleophiles with carbonyl compounds, we need to analyze the influence of different substituents on the carbonyl carbon. Here’s a step-by-step breakdown of the reasoning:

### Step 1: Identify the Carbonyl Compounds
We are considering three carbonyl compounds:
1. CH3C(=O)Cl (Carbonyl chloride)
2. CH3C(=O)NH2 (Amide)
3. CH3C(=O)OCH3 (Ester)

### Step 2: Analyze the Effect of Substituents
- **Carbonyl Chloride (CH3C(=O)Cl)**: The chlorine atom is a good leaving group and exhibits a -I (inductive) effect, which increases the positive character of the carbonyl carbon. This makes it more susceptible to nucleophilic attack.

- **Amide (CH3C(=O)NH2)**: The amine group (NH2) is a +R (resonance) donor, which means it can donate electron density to the carbonyl carbon, reducing its positive character and making it less reactive compared to carbonyl chloride.

- **Ester (CH3C(=O)OCH3)**: The methoxy group (OCH3) also acts as a +R donor, similar to the amine group. However, oxygen is more electronegative than nitrogen, which means it holds onto its electrons more tightly. This results in a greater reduction of the positive character of the carbonyl carbon compared to the amide.

### Step 3: Determine the Reactivity Order
Based on the analysis:
- **Carbonyl Chloride (CH3C(=O)Cl)** is the most reactive due to the presence of a good leaving group (Cl) and the strong +I effect.
- **Amide (CH3C(=O)NH2)** is next, as it has a +R effect but is less reactive than carbonyl chloride.
- **Ester (CH3C(=O)OCH3)** is the least reactive due to the strong +R effect from the methoxy group, which stabilizes the carbonyl carbon.

Thus, the correct reactivity order with respect to nucleophiles is:
**Cl > NH2 > OCH3**

### Final Answer
The correct reactivity order with the nucleophile is: **Cl > NH2 > OCH3** (Option A).

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