Question 23M.3.SL.TZ1.2
| Date | May 2023 | Marks available | [Maximum mark: 7] | Reference code | 23M.3.SL.TZ1.2 |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Deduce, Identify, Sketch | Question number | 2 | Adapted from | N/A |
Metals A, B, C, D, and E were placed in sulfate solutions.
The results are given where ✓ = reaction occurred and = no reaction.
| Metal | ASO4 (aq) | BSO4 (aq) | CSO4 (aq) | DSO4 (aq) | ESO4 (aq) |
| A | — | ✓ | ✗ | ✓ | ✓ |
| B | ✗ | — | ✗ | ✓ | ✓ |
| C | ✓ | ✓ | — | ✓ | ✓ |
| D | ✗ | ✗ | ✗ | — | ✓ |
| E | ✗ | ✗ | ✗ | ✗ | — |
Identify the oxidation state of metal A in ASO4.
[1]
+2/II ✓
Do not accept A2+, A+2, 2 OR 2+.
Deduce the activity series of the metals.
[1]
C A B D E ✓
Do not accept reverse order unless the answer makes it clear which is the most reactive.
Sketch the voltaic cell that produces the greatest electromotive force, EMF, using the information in part (a). Label the direction of electron flow, salt bridge, anode, cathode, the metals (A–E) and solutions used in each half-cell.
[4]
two half cells with electrodes, solutions, salt bridge and connecting wire ✓
C as anode AND E as cathode ✓
CSO4 AND ESO4 «solutions» labelled ✓
electron flow shown «on wire» from more reactive to less reactive metal ✓
Voltmeter not needed.
Accept salt bridge even if not labelled.
Do not award M1 if a battery is included.
Do not award M1 if liquid level not shown in container, or if electrodes and ends of salt bridge are not in solutions.
Accept salt of C/C2+«(aq») AND salt of E/E2+«(aq)» for M3.
Deduce the products formed at the electrodes during the electrolysis of molten zinc bromide.
Anode (positive electrode): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cathode (negative electrode): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[1]
Anode: bromine / Br2
AND
Cathode: zinc / Zn ✓
Do not accept bromide.
Do not accept Br for Br2