Numford
Oxidation number

O in H₂O₂

O is −1 in hydrogen peroxide.

Oxidation number

Type a formula or an ion: K2Cr2O7, Cr2O7 2-, MnO4-, NH4+ or K4[Fe(CN)6]. Put a known ion in brackets when two elements are unknown. Pick an element to solve for it.

O−1

  1. Hydrogen is +1 when bonded to non-metals.
  2. Oxygen is −1 in peroxides; the sum below shows this is one.
  3. The oxidation numbers add up to the charge, 0: 2(+1) + 2x = 0.
  4. 2x = −2, so x = −1.
Rule steps

How to find it

  1. Hydrogen is +1 when bonded to non-metals.
  2. Oxygen is −1 in peroxides; the sum below shows this is one.
  3. The oxidation numbers add up to the charge, 0: 2(+1) + 2x = 0.
  4. 2x = −2, so x = −1.
Every atom

All the oxidation numbers in H₂O₂

  • H +12 atoms, hydrogen
  • O −12 atoms, peroxide
Questions

O in H₂O₂: quick answers

What is the oxidation number of O in H₂O₂?

O in H₂O₂ (hydrogen peroxide) is −1.

How do you find the oxidation number of O in H₂O₂?

Hydrogen is +1 when bonded to non-metals. Oxygen is −1 in peroxides; the sum below shows this is one. The oxidation numbers add up to the charge, 0: 2(+1) + 2x = 0. 2x = −2, so x = −1.

What are the oxidation numbers of the other atoms in H₂O₂?

H +1. Together with O at −1 they add up to the charge of the compound, 0.

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