Metals in salt solutions – predicting reactions from standard electrode potentials
ChemistryReactions & RedoxAges 17–18Virtual lab
Use it with your class: students open it from a link or a QR code, with no account needed.
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Dip a strip of Mg, Zn, Fe, Cu or Ag into CuSO₄, AgNO₃, FeSO₄ or ZnSO₄ solution. Students predict whether a reaction takes place from the standard electrode potentials E°, then watch metal deposit on the strip, the blue color of Cu²⁺ fade and the mass of the strip change on a balance. The ionic equation, E°cell, Δm and a results table are shown for every trial.
Lesson: Standard electrode potentials – reactions of metals with salt solutions
What it shows
Whether a metal displaces another metal from a salt solution can be predicted from standard electrode potentials. The metal with the more negative E° is the stronger reducing agent: it loses electrons and dissolves, while the ion of the metal with the more positive E° gains electrons and is deposited. The reaction is feasible when E°cell = E°(ion) − E°(metal) is positive. The mass change follows from the stoichiometry: a zinc strip in CuSO₄ gets lighter, because each 65.4 g of zinc that dissolves deposits only 63.5 g of copper, whereas iron in CuSO₄ and copper in AgNO₃ gain mass.
How to use
Choose a Metal strip and a Salt solution, and set the concentration and volume. Before dipping, click Reaction or No reaction to record a prediction based on the E° scale, then click Dip the metal strip or tap the picture. Watch the deposit form, the solution color change and the balance reading, and check the ionic equation and Δm. The results table marks each prediction right or wrong, so students can test many combinations.
Parameters you can change
- Metal strip Magnesium Mg, Zinc Zn, Iron Fe, Copper Cu, Silver Ag
- Salt solution Copper(II) sulfate CuSO₄, Silver nitrate AgNO₃, Iron(II) sulfate FeSO₄, Zinc sulfate ZnSO₄
- Salt solution concentration 0.05–1 mol/L
- Solution volume 20–100 mL
- Simulation speed 0.5–3 ×
Questions to explore
- Why can copper reduce Ag⁺ ions but not Fe²⁺ ions?
- Does a zinc strip gain or lose mass in CuSO₄ solution, and what is Δm when 0.025 mol of Cu²⁺ has reacted?
- How would you arrange Mg²⁺, Zn²⁺, Fe²⁺, Cu²⁺ and Ag⁺ in order of increasing oxidizing power?
