If the electron pair forming a bond between two atoms A and B is not in the centre, then the bond is

Options

A. single bond
B. polar bond
C. non-polar bond
D. `pi`-bond.

Explanation

To determine the type of bond between two atoms A and B when the electron pair is not centered, we can follow these steps:

### Step 1: Understand the Concept of Bonding
- Bonds are formed when atoms share or transfer electrons. The distribution of these electrons can affect the bond's characteristics.

**Hint:** Recall that the position of the electron pair can influence the bond's polarity.

### Step 2: Define the Types of Bonds
- **Single Bond:** A bond formed by the sharing of one pair of electrons.
- **Nonpolar Bond:** A bond where the electron pair is shared equally between two atoms of similar electronegativity.
- **Polar Bond:** A bond where the electron pair is shared unequally due to a difference in electronegativity between the two atoms.
- **Pi Bond:** A bond that results from the side-to-side overlap of p orbitals, typically found in double and triple bonds.

**Hint:** Focus on how the electronegativity of the atoms affects the sharing of electrons.

### Step 3: Analyze the Given Condition
- The question states that the electron pair is "not in the center." This implies that one atom is attracting the shared electrons more strongly than the other, indicating an unequal sharing.

**Hint:** Think about what happens when one atom is more electronegative than the other.

### Step 4: Identify the Correct Bond Type
- Since one atom (let's say atom B) is more electronegative, it will attract the shared electron pair closer to itself. This results in a partial negative charge on atom B and a partial positive charge on atom A, leading to a polar bond.

**Hint:** Remember that the unequal sharing of electrons due to electronegativity differences is what defines a polar bond.

### Conclusion
- Therefore, if the electron pair forming a bond between two atoms A and B is not in the center, the bond is a **polar bond**.

**Final Answer:** The bond is a polar bond.