Water’s polarity enables hydrogen bonding critical for biomolecular structure, enzyme function, and cellular processes. Oxygen’s electronegativity (3.44) exceeds hydrogen’s (2.20), creating polar covalent O-H bonds with partial negative charge (δ⁻) on oxygen and partial positive (δ⁺) on hydrogens.

The correct answer is (B) bonding electrons being attracted more to oxygen, establishing the dipole moment (1.85 D) responsible for water’s unique solvent properties.

Why (B) Oxygen’s Electronegative Pull Creates Polarity

In H₂O’s bent VSEPR structure (104.5° bond angle), oxygen pulls bonding electrons closer, creating δ⁻O and δ⁺H₂ poles. Lone pairs enhance molecular asymmetry. Result: permanent dipole enabling hydrogen bonds fundamental to DNA structure, protein folding, and membrane fluidity.

Explanation of All Options

Each option tests fundamental chemical bonding concepts:

• (A) Its tetrahedral structure
  Wrong. Electron geometry tetrahedral, molecular geometry bent. CH₄ (perfect tetrahedron) nonpolar despite tetrahedral arrangement.

• (B) Bonding electrons attracted more to oxygen
  Correct. Electronegativity difference (ΔEN = 1.24) creates polar covalent bonds. Oxygen’s higher nuclear charge pulls shared electrons.

• (C) Bonding electrons attracted more to hydrogen
  Incorrect. Opposite of reality—hydrogen less electronegative, becomes δ⁺. Would predict reverse polarity.

• (D) Its weak electrolytic property
  No. Pure water poor conductor (10⁻⁷ M H⁺/OH⁻). Polarity precedes ionization; electrolytic property consequence, not cause.

Quick Polarity Factor Analysis

Biotech relevance: Water polarity dictates biomolecule solubility (polar amino acids hydrophilic). Critical for chromatography, electrophoresis, PCR buffer design. Memory trick: “Oxygen hogs electrons → δ⁻O, δ⁺H → polar water.”