Slowest rate of electrophilic addition will take place in

Options

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B.
C.
D.

Answer

To determine the slowest rate of electrophilic addition in alkenes, we need to analyze the electron density of the alkenes in question. The electrophilic addition reaction is influenced by the electron density of the double bond in the alkene; the lower the electron density, the slower the reaction.

### Step-by-Step Solution:

1. **Identify the Alkenes**:
We need to consider the given options for the alkenes. Let's assume we have four alkenes with different substituents.

2. **Understand Electrophilic Addition**:
Electrophilic addition involves an electrophile attacking the electron-rich double bond of an alkene. The rate of this reaction is influenced by the electron density of the alkene.

3. **Analyze Electron Density**:
- Alkene with electron-donating groups (like -OH or -CH3) will have higher electron density, making them more reactive towards electrophiles.
- Alkene with electron-withdrawing groups (like -NO2) will have lower electron density, making them less reactive and thus slower in electrophilic addition.

4. **Evaluate Each Alkene**:
- If one alkene has a -NO2 group, it will exhibit a -M (minus mesomeric) effect, withdrawing electron density from the double bond, leading to a slower reaction.
- Compare this with other alkenes that have groups like -OH (which has a +M effect) or -CH3 (which has a +I effect). These groups increase electron density.

5. **Determine the Slowest Alkene**:
After analyzing the effects of the substituents, we find that the alkene with the -NO2 group has the least electron density and thus will have the slowest rate of electrophilic addition.

6. **Conclusion**:
Therefore, the alkene with the -NO2 substituent will exhibit the slowest rate of electrophilic addition.

### Final Answer:
The slowest rate of electrophilic addition will take place in the alkene with the -NO2 group.

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