The bond angle in H₂O is 104.5°. This fact can be explained with the help of:

• (A) Valence shell electron pair repulsion theory (VSEPR)
• (B) Molecular orbital theory
• (C) Presence of hydrogen bond
• (D) Electronegativity difference between hydrogen and oxygen

The bond angle in H₂O being 104.5° can be best explained by the Valence Shell Electron Pair Repulsion (VSEPR) theory.

Why VSEPR Theory Matters

This theory states that electron pairs around a central atom will arrange themselves to minimize repulsion. In water, the oxygen atom has two lone pairs and two hydrogen atoms bonded to it.

Understanding the Geometry

• The lone pairs occupy more space than bonding pairs.
• This pushes the hydrogen atoms closer together.
• As a result, the bond angle is slightly less than the ideal tetrahedral angle of 109.5°.

Thus, the correct answer is (A) Valence shell electron pair repulsion theory (VSEPR), as it effectively explains the observed bond angle in water. Other options do not directly account for the molecular shape and angles in this context.