Redox Tracker (Oxidation Numbers)
Analyse any redox reaction you type, see who is oxidised and reduced, then test yourself.
Use -> for the arrow and + (with spaces) between species. Plain numbers are subscripts: Ca(OH)2. Write ion charges with a caret: Cu^2+, MnO4^-, Fe^3+, H^+.
| Element | Oxidation number | Electrons | What happened |
|---|
Show every oxidation number
Test yourself
Work out the oxidation number of every element, then answer the three questions. Use + or − signs (for example +5, -2).
About the Redox Tracker (Oxidation Numbers)
Free redox reaction analyser. Type your own reaction (even unbalanced), get it balanced, see oxidation numbers, oxidising and reducing agents and electrons transferred, or test yourself with a self-check quiz. Built for electrochemistry, the redox tracker (oxidation numbers) runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Analyse any redox reaction you type, see who is oxidised and reduced, then test yourself. Use it to explore electrochemistry ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Redox Tracker (Oxidation Numbers)
- Press "Transfer electrons", "Reset", "Test myself" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Type your own reaction, for example Sn^2+ + Fe^3+ -> Sn^4+ + Fe^2+
- Try Cu + HNO3 -> Cu(NO3)2 + NO2 + H2O and find which element changes oxidation number.
- Press Test myself, fill in every oxidation number, then press Check.
- Find the disproportionation example: one species is both oxidised and reduced.
Key ideas you can learn
- Oxidation is loss of electrons and reduction is gain of electrons (OIL RIG).
- The species that is oxidised is the reducing agent.
- The species that is reduced is the oxidising agent.
Where this is used in the real world
Redox reactions power batteries, rust, respiration, photosynthesis, bleaching and combustion.
Who is this simulation for?
Chemistry students studying redox, batteries and electrolysis, and teachers who want a clear picture of where the electrons go.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
What does OIL RIG mean?
Oxidation Is Loss, Reduction Is Gain, of electrons.
Can oxidation happen without reduction?
No. Electrons lost by one species must be gained by another, so the two always happen together.
Is the Redox Tracker (Oxidation Numbers) free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Redox Tracker (Oxidation Numbers) work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.