Oxidation and reduction as loss and gain of electrons, ionic equations for displacement, and the salt and gas made when a metal reacts with an acid.
What you will learn
- Use OIL RIG to say which species is oxidised and which is reduced
- Choose the ionic equation for a displacement and spot spectator ions
- Name the products of a metal and an acid, and test for hydrogen
OIL RIG (Higher)
Oxygen is not always involved, so chemists also define oxidation and reduction by electrons:
Oxidation Is Loss of electrons
Reduction Is Gain of electrons
In a displacement the more reactive metal atom loses electrons and the ion of the less reactive metal gains them:
- Zn + Cu²⁺ → Zn²⁺ + Cu
- Zn → Zn²⁺: zinc loses 2 electrons, so zinc is oxidised
- Cu²⁺ → Cu: copper ions gain 2 electrons, so they are reduced
A reaction in which one substance is oxidised and another is reduced is a redox reaction.
The rest of this lesson and its 8 practice questions are locked.
In this lesson
- OIL RIG (Higher)
- Ionic equations (Higher)
- Metals with acids
- Try it: Find the ion charges
8 practice questions, marked as you go; about 20 minutes in all.
Key terms
Redox, Spectator ions, Salt
In this unit: Chemical changes: reactivity, acids and electrolysis
The reactivity series and metal extraction, oxidation and reduction, acids, salts and pH, titrations, and electrolysis of melts and solutions.