This question is about electrolysis.
A student investigated the following hypothesis:
'The electrolysis of an aqueous salt solution produces a solid metal at the negative electrode and a gas at the positive electrode.'
What observation would be made at each electrode if the hypothesis is correct?
- Observation for solid metal at the negative electrode
- Observation for gas at the positive electrode
Table 1 shows the student's results.
Table 1
| Aqueous Salt Solution | Product at the negative electrode | Product at the positive electrode |
|---|---|---|
| Copper(II) sulfate | Copper | Oxygen |
| Sodium chloride | Hydrogen | Chlorine |
| Tin(II) chloride | Tin | Chlorine |
Which salt solution in Table 1 does not support the student's hypothesis? Give a reason for your answer.
- Salt solution
- Reason
Graphite is used for the electrodes in this experiment. Give two properties of graphite that make it suitable for this use.
A different student investigated the movement of ions during electrolysis using the apparatus shown in Figure 1.
The green crystal contains:
- green-coloured positive ions
- colourless negative ions.
The green crystal dissolves in the electrolyte solution.
State and explain where the green colour moves when the current is switched on.
- Movement of the green colour
- Reason