A student carries out an investigation to compare the reactivities of four metals: magnesium, lead, iron, and X.
He adds strips of iron to the aqueous solutions of the nitrates of each metal.
After a few minutes, he removes the strips of iron and examines them.
The first table shows his results:
| Solution | Result |
|---|---|
| magnesium nitrate | no change |
| lead(II) nitrate | dark grey coating on iron |
| iron(II) nitrate | no change |
| nitrate of metal X | grey coating on iron |
Name the substance that causes the dark grey coating on the iron in the lead(II) nitrate solution.
State why there is no change in the experiment with iron(II) nitrate solution.
The student repeats the experiment using strips of metal X instead of iron. The table below shows his results:
| Solution | Result |
|---|---|
| magnesium nitrate | no change |
| lead(II) nitrate | grey coating on X |
| iron(II) nitrate | no change |
| nitrate of metal X | no change |
Using information from both tables, place the metals magnesium, lead, iron, and X in order of decreasing reactivity (from most reactive to least reactive).
Zinc reacts with an aqueous solution of copper(II) sulfate. The reaction can be represented by the ionic equation:
Zn(s)+Cu2+(aq)→Zn2+(aq)+Cu(s) \text{Zn(s)} + \text{Cu}^{2+}\text{(aq)} \rightarrow \text{Zn}^{2+}\text{(aq)} + \text{Cu(s)} Zn(s)+Cu2+(aq)→Zn2+(aq)+Cu(s)State why this reaction is described as a redox reaction.
Explain, in terms of electrons, which species is behaving as an oxidising agent in this reaction.
