Question

why hydrogen peroxide is very unstable

Answer 1

Hydrogen peroxide is thermodynamically unstable and decomposes to form H2O and O2 with aΔH=of −98.2 kJ/mol.Its decomposition is catalysed by metal ions, bases and temperature.

Answer 2

the combination is H2O2, an unstablepowerful oxidant. ... Hydrogen peroxide is very unstable and breaks down readily into water and a single oxygen molecule. Oxygen is stableonly when the molecules are pairs (O2). A single oxygen molecule is a strong oxidizing and disinfecting agent.