The - I effect of `-NO_(2),-CN,-COOH,-Cl` decreases in the order

Options

A. `-NO_(2)gt-CNgt-COOHgt-Cl`
B. `-Clgt-COOHgt-CNgt-NO_(2)`
C. `-CNgt-NO_(2)gt-Clgt-COOH`
D. `-COOHgt-CNgt-NO_(2)gt-Cl`

Explanation

To determine the decreasing order of the -I (minus inductive) effect of the groups -NO2, -CN, -COOH, and -Cl, we need to analyze the electron-withdrawing ability of each group.

### Step-by-Step Solution:

1. **Understanding the -I Effect**:
The -I effect refers to the electron-withdrawing effect of substituents through sigma bonds. Groups that are more electronegative or have a strong ability to attract electrons will exhibit a stronger -I effect.

2. **Identifying the Groups**:
The groups we need to compare are:
- -NO2 (Nitro group)
- -CN (Cyano group)
- -COOH (Carboxylic acid group)
- -Cl (Chloro group)

3. **Analyzing Each Group**:
- **-NO2**: The nitro group is highly electronegative due to the presence of nitrogen (N) and the resonance stabilization it can provide. It is one of the strongest electron-withdrawing groups.
- **-CN**: The cyano group also has a strong -I effect due to the triple bond between carbon and nitrogen, making it very electronegative.
- **-COOH**: The carboxylic acid group has both a carbonyl (C=O) and a hydroxyl (OH) group, which can also withdraw electrons, but it is less effective than -NO2 and -CN.
- **-Cl**: Chlorine is less electronegative than the other groups mentioned and has a weaker -I effect compared to the others.

4. **Ranking the Groups**:
Based on the analysis:
- **Strongest -I effect**: -NO2
- **Next**: -CN
- **Next**: -COOH
- **Weakest -I effect**: -Cl

5. **Final Order**:
Therefore, the order of the -I effect from strongest to weakest is:
**-NO2 > -CN > -COOH > -Cl**