Maximum number of H-bonds that can be formed by a water molecule is .

Options

A. `2`
B. `3`
C. `4`
D. `6`

Explanation

To determine the maximum number of hydrogen bonds that can be formed by a water molecule, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Water**:
- A water molecule (H₂O) consists of one oxygen atom and two hydrogen atoms. The oxygen atom is bonded to the two hydrogen atoms.

2. **Identify the Lone Pairs on Oxygen**:
- The oxygen atom in a water molecule has two lone pairs of electrons. These lone pairs are crucial for hydrogen bonding.

3. **Determine the Hydrogen Bonding Capacity of Hydrogen Atoms**:
- Each hydrogen atom in a water molecule can form one hydrogen bond with the oxygen atom of another water molecule.

4. **Count the Total Hydrogen Bonds**:
- Since there are two hydrogen atoms in a water molecule, each can form a hydrogen bond with another water molecule. This gives us 2 hydrogen bonds from the hydrogen atoms.
- Additionally, the oxygen atom can participate in hydrogen bonding due to its two lone pairs. Each lone pair can form a hydrogen bond with a hydrogen atom from another water molecule, contributing 2 more hydrogen bonds.

5. **Calculate the Maximum Number of Hydrogen Bonds**:
- Therefore, the total number of hydrogen bonds that can be formed by one water molecule is:
- 2 (from hydrogen atoms) + 2 (from lone pairs on oxygen) = 4 hydrogen bonds.

6. **Conclusion**:
- The maximum number of hydrogen bonds that can be formed by a water molecule is 4.

### Final Answer:
The maximum number of hydrogen bonds that can be formed by a water molecule is **4**.

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