Which of the following statement is correct ?

Options

A. `+` l group stabilises a carbocation
B. `+` l group stabilises a carbanion
C. `+` l group destabilises a carbocation
D. `+` l group stabilises a free radical

Answer

To determine which of the statements regarding the +I (positive inductive) group is correct, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Carbocation, Carbanion, and Free Radical:**
- A **carbocation** is a carbon atom with a positive charge, having only 6 electrons in its valence shell.
- A **carbanion** is a carbon atom with a negative charge, having 8 electrons in its valence shell.
- A **free radical** is a carbon atom with an unpaired electron, having 7 electrons in its valence shell.

2. **Analyzing the Statements:**
- **Statement 1:** "+I group stabilizes a carbocation."
- A carbocation is electron-deficient (6 electrons). A +I group (electron-donating group) can donate electrons, thus stabilizing the carbocation.
- **Conclusion:** This statement is **correct**.

- **Statement 2:** "+I group stabilizes a carbanion."
- A carbanion is electron-rich (8 electrons). Adding a +I group, which donates electrons, would destabilize the carbanion by increasing electron density.
- **Conclusion:** This statement is **incorrect**.

- **Statement 3:** "+I group destabilizes a carbocation."
- As established, a +I group stabilizes a carbocation by donating electrons. Therefore, this statement is incorrect.
- **Conclusion:** This statement is **incorrect**.

- **Statement 4:** "+I group stabilizes a free radical."
- A free radical has 7 electrons and is also electron-deficient. A +I group can donate electrons to stabilize the free radical.
- **Conclusion:** This statement is **correct**.

3. **Final Conclusion:**
- The correct statements are:
- Statement 1: "+I group stabilizes a carbocation."
- Statement 4: "+I group stabilizes a free radical."

### Summary of Correct Statements:
- The correct statements are:
- +I group stabilizes a carbocation.
- +I group stabilizes a free radical.