In peroxide, oxygen's oxidation number is

In peroxide, oxygen's oxidation number is

• A. Always -2
• B. Always -1
• C. Usually -2, But -1 In Peroxides
• D. Plus One

Answer: (C)

Oxidation numbers are a way to assign electrons in a compound to the atoms involved. Oxygen is normally -2 because it tends to attract electrons strongly. In peroxides, there is an O–O single bond between two oxygens, and for the purpose of oxidation states, the shared electrons are counted as belonging to neither oxygen more than the other, giving each oxygen an oxidation state of -1. For example, in hydrogen peroxide (H2O2), the two hydrogens are +1 each, and the two oxygens are -1 each, balancing to a neutral molecule. That’s why the best description is that oxygen is usually -2, but -1 in peroxides.

Oxidation numbers are a way to assign electrons in a compound to the atoms involved. Oxygen is normally -2 because it tends to attract electrons strongly. In peroxides, there is an O–O single bond between two oxygens, and for the purpose of oxidation states, the shared electrons are counted as belonging to neither oxygen more than the other, giving each oxygen an oxidation state of -1. For example, in hydrogen peroxide (H2O2), the two hydrogens are +1 each, and the two oxygens are -1 each, balancing to a neutral molecule. That’s why the best description is that oxygen is usually -2, but -1 in peroxides.