O Level Chemistry – Definition of Redox

• Oxidation describes those reactions in which oxygen or the halogens are added to a substance or hydrogen is removed from it.
• Reduction describes those reactions in which oxygen or the halogens are removed from the substance or hydrogen is added to it.
• Oxidation can also be determined when electrons are lost by an atom or a group of atoms.
• Reduction can be determined when electrons are gained by an atom or a group of atoms.
• When an element is oxidised, its oxidation number increases.
• When an element is reduced, its oxidation number decreases.

Oxidation & Reduction always occur together => and we call this REDOX REACTIONS.

At the start of this year around Jan/Feb period, we had actually discussed couple of questions on Redox. Do check out those archives to look at several exam-based questions.

Related Articles:

• O-Level Chemistry: 5 Rules to Assign Oxidation States (Redox Reactions)
• O Levels Chemistry Tips Blog Marathon – Day 5
• O Level Chemistry – More Questions on REDOX
• O Levels Chemistry Tips Blog Marathon – Day 4
• O Level Chemistry – Isotopes Part 2