Which of the following types of reactions occurs when a substituent has got a double bond with evenly distributed `pi` electron cloud?

Options

A. Electrophilic addition
B. Nucleophilic addition
C. Any of the I and II
D. None of the above

Answer

To solve the question regarding the type of reaction that occurs when a substituent has a double bond with an evenly distributed pi electron cloud, we can follow these steps:

### Step 1: Understand the Structure
We start by recognizing that the question refers to a substituent with a double bond. In organic chemistry, a double bond consists of one sigma bond and one pi bond. The pi bond is formed by the sideways overlap of p-orbitals.

**Hint:** Identify the type of bond present in the substituent and its characteristics.

### Step 2: Analyze the Electron Distribution
The question specifies that the pi electron cloud is "evenly distributed." This means that the electrons in the pi bond are shared equally between the two atoms involved in the double bond. For example, in alkenes (C=C), the two carbon atoms have similar electronegativity, leading to an even distribution of the pi electrons.

**Hint:** Consider how the electronegativity of the atoms in the double bond affects the electron cloud.

### Step 3: Identify Reaction Types
In organic chemistry, different types of reactions are associated with different types of electron distributions. For alkenes, which have evenly distributed pi electrons, the characteristic reaction is electrophilic addition. This involves an electrophile attacking the double bond, resulting in the addition of new atoms or groups across the double bond.

**Hint:** Recall the common reactions associated with alkenes and how they differ from other types of compounds.

### Step 4: Conclude the Type of Reaction
Given that the substituent has a double bond with evenly distributed pi electrons, the reaction that occurs is an electrophilic addition reaction. This is because the double bond can readily react with electrophiles, leading to the formation of more stable products.

**Hint:** Summarize the key characteristics of the reaction type associated with alkenes.

### Final Answer
The type of reaction that occurs when a substituent has a double bond with an evenly distributed pi electron cloud is **electrophilic addition**.