When `-CH_(3), CH_(3) - underset(CH_(3))underset(|)(CH) - " and " CH_(3) - underset(CH_(3))underset(|) overset(CH_(3))overset(|)C - ` groups are introduced on benzene ring then correct order of their inductive effect is

Options

A. `CH_(3) - gt CH_(3) - underset(CH_(3))underset(|) (CH) - gt CH_(3) - underset(CH_(3))underset(|) overset(CH_(3))overset(|)C - `
B. ` CH_(3) - underset(CH_(3))underset(|) overset(CH_(3))overset(|)C - gtCH_(3) - underset(CH_(3))underset(|)(CH) - gt CH_(3) - `
C. `CH_(3) - underset(CH_(3))underset(|) (CH) - gt CH_(3) gt CH_(3) - underset(CH_(3))underset(|) overset(CH_(3))overset(|)C - `
D. ` CH_(3) - underset(CH_(3))underset(|) overset(CH_(3))overset(|)C - gt CH_(3) - gt CH_(3) - underset(CH_(3))underset(|) (CH) - `

Answer

To determine the correct order of the inductive effect of the given groups when introduced on a benzene ring, we need to analyze the groups one by one. The groups in question are:

1. **-CH3**
2. **-CH(CH3)2** (which can be interpreted as a carbon with one hydrogen and two methyl groups)
3. **-C(CH3)3** (a carbon with three methyl groups)

### Step-by-Step Solution:

**Step 1: Analyze the first group (-CH3)**
The -CH3 group (methyl group) has a weak +I (positive inductive) effect. This means it slightly pushes electron density towards the benzene ring but is not very strong in doing so.

**Step 2: Analyze the second group (-CH(CH3)2)**
The -CH(CH3)2 group has two methyl groups attached to a carbon, which increases the +I effect compared to a single -CH3 group. The two methyl groups will push more electron density towards the benzene ring than a single methyl group.

**Step 3: Analyze the third group (-C(CH3)3)**
The -C(CH3)3 group has three methyl groups attached to a single carbon. This group will exert the strongest +I effect among the three groups because it has the maximum number of methyl groups donating electron density towards the benzene ring.

**Step 4: Compare the inductive effects**
Now we can compare the inductive effects:
- The -CH3 group has the weakest +I effect.
- The -CH(CH3)2 group has a moderate +I effect.
- The -C(CH3)3 group has the strongest +I effect.

**Step 5: Establish the order of inductive effect**
Based on the analysis:
- The order of the inductive effect from weakest to strongest is:
- **-CH3 < -CH(CH3)2 < -C(CH3)3**

### Final Answer:
The correct order of their inductive effect is:
**-CH3 < -CH(CH3)2 < -C(CH3)3**

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