Question 22M.2.sl.TZ1.b
| Date | May 2022 | Marks available | [Maximum mark: 2] | Reference code | 22M.2.sl.TZ1.b |
| Level | sl | Paper | 2 | Time zone | TZ1 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
Magnesium is a reactive metal often found in alloys.
Suggest an experiment that shows that magnesium is more reactive than zinc, giving the observation that would confirm this.
[2]
Alternative 1
put Mg in Zn2+(aq) ✔
Zn/«black» layer forms «on surface of Mg» ✔
Award [1 max] for “no reaction when Zn placed in Mg2+(aq)”.
Alternative 2
place both metals in acid ✔
bubbles evolve more rapidly from Mg
OR
Mg dissolves faster ✔
Alternative 3
construct a cell with Mg and Zn electrodes ✔
bulb lights up
OR
shows (+) voltage
OR
size/mass of Mg(s) decreases «over time»
OR
size/mass of Zn increases «over time»
Accept “electrons flow from Mg to Zn”.
Accept Mg is negative electrode/anode
OR
Zn is positive electrode/cathode
Accept other correct methods.
Many candidates gained some credit by suggesting voltaic cell or a displacement reaction, but most could not gain the second mark and the reason was often a failure to be able to differentiate between "what occurs" and "what is observed".
