Which of the following statements is/are correct?

Options

A. Inductive effect causes permanent polarity in the molecular
B. Free radicals have odd electron in `p-`orbital.
C. Inductive effect is a distance dependent.
D. Mesomeric effect is distance dependent.

Explanation

To determine which of the statements given in the question are correct, we will analyze each statement one by one.

### Step 1: Analyze the First Statement
**Statement:** Inductive effect causes permanent polarity in the molecule.

**Analysis:**
- The inductive effect refers to the permanent polarization of a bond due to the electronegativity difference between atoms.
- It results in a permanent dipole moment in the molecule.
- For example, in a molecule like chloroethane (C2H5Cl), the chlorine atom pulls electron density towards itself, creating a permanent dipole.

**Conclusion:** This statement is **true**.

### Step 2: Analyze the Second Statement
**Statement:** Free radicals have odd electrons in p orbital.

**Analysis:**
- Free radicals are species that contain an unpaired electron, which makes them highly reactive.
- The unpaired electron can indeed be found in the p orbital. For example, in the hydroxyl radical (•OH), the oxygen atom has one unpaired electron in its p orbital.

**Conclusion:** This statement is **true**.

### Step 3: Analyze the Third Statement
**Statement:** Inductive effect is a distance-dependent effect.

**Analysis:**
- The inductive effect diminishes with distance from the electronegative atom or group.
- As you move further away from the electronegative atom, the effect becomes weaker, indicating that it is indeed distance-dependent.

**Conclusion:** This statement is **true**.

### Step 4: Analyze the Fourth Statement
**Statement:** Mesomeric effect is a distance-dependent one.

**Analysis:**
- The mesomeric effect (or resonance effect) involves the delocalization of electrons across a molecule, which is not dependent on distance in the same way as the inductive effect.
- For example, in a benzene ring with a substituent that exhibits a +M effect, the resonance occurs primarily at the ortho and para positions, regardless of the distance from the substituent.

**Conclusion:** This statement is **false**.

### Final Summary
- **Correct Statements:** 1, 2, and 3 are correct.
- **Incorrect Statement:** 4 is incorrect.