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🧪 Chemistry  ·  Hydrogen  ·  NEET & JEE

Why does H<sub>2</sub>O<sub>2</sub> have a higher boiling point (150°C) than water (100°C) despite having similar molecular weight?

Answer: Both O atoms in H 2 O 2 form hydrogen bonds (more H-bond donors and acceptors per molecule).

  • A Both O atoms in H<sub>2</sub>O<sub>2</sub> form hydrogen bonds (more H-bond donors and acceptors per molecule)
  • B H<sub>2</sub>O<sub>2</sub> carries a significant degree of ionic character unlike water as widely reported
  • C H<sub>2</sub>O<sub>2</sub> molecules are generally much larger in physical size than water in standard practice
  • D H<sub>2</sub>O<sub>2</sub> lacks hydrogen bonding largely, relying mainly on dispersion forces under most conditions encountered

Correct answer: A. Both O atoms in H<sub>2</sub>O<sub>2</sub> form hydrogen bonds (more H-bond donors and acceptors per molecule)

Explanation: H<sub>2</sub>O<sub>2</sub> has two O-H bonds and two oxygen lone pairs, enabling more extensive hydrogen bonding than water (one O, two O-H).

Hydrogen Bonding Network in WaterOHHOHHOHHOHHDashed green lines = hydrogen bonds (weaker than O-H covalent bonds)

Each water molecule's O-H bonds (covalent, solid) can hydrogen-bond (dashed) to neighbouring molecules, forming an extended network responsible for water's unusually high boiling point and density anomaly.

Concept context

The simplest and most abundant element in the universe. Study its unique position in the periodic table, isotopes (protium, deuterium, tritium), properties of water and hydrogen peroxide, and industrial uses.

Read the full Hydrogen notes →