Grade 12 Physical Sciences · Chemical Change · Paper 2 (Chemistry)

Electrochemistry Grade 12

Real Electrochemistry past paper questions and answers from 2023 to 2025, with each memo split into the ticks examiners give. Try one, mark yourself, and see exactly which skill cost you marks.

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Question 1.9 · November 2025 · Paper 2 · National (DBE) · 2 marks

Various options are provided as possible answers to the following questions. Each question has only ONE correct answer.

1.9 A galvanic cell consists of the following half-cells:

Fe^{3 +} (aq) ∣ Fe^{2 +} (aq)

Ni^{2 +} (aq) ∣ Ni(s)

Which ONE of the following statements is CORRECT for this cell?(2)

A $Ni^{2 +}$ is reduced and $Fe^{2 +}$ is oxidised.
B $Ni^{2 +}$ is oxidised and $Fe^{3 +}$ is reduced.
C Pt is the electrode at the cathode.
D Ni is the electrode at the cathode.

Work it out on paper first. Then mark yourself with the official memo, one tick at a time.

Electrochemistry skills

Each skill is one thing a memo gives a tick for. Tap one for its own questions, notes and videos.

More Electrochemistry Grade 12 questions and answers

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4. Question 8.5.3 · May/June 2025 · Paper 2 · National (DBE) · 3 marks
The simplified diagram below shows a cell that can be used to measure the standard electrode potential of the half-reaction represented by the equation below.

$Fe^{3 +} (aq) + e^{-} ⇌ Fe^{2 +} (aq)$
8.5 Write down the:
8.5.3 Cell notation for this cell(3)
Show the memo (3 ticks)Memo
1. ✓
  Anode half-cell $Pt(s) ∣ H_{2} (g) ∣ H^{+} (aq)$
  1 mark · Describe a galvanic cell
2. ✓
  Salt bridge $∥$
  1 mark · Describe a galvanic cell
3. ✓
  Cathode half-cell $Fe^{3 +} (aq), Fe^{2 +} (aq) ∣ Pt(s)$
  1 mark · Describe a galvanic cell
5. Question 8.6.2 · May/June 2024 · Paper 2 · National (DBE) · 2 marks
The relationship between the concentration of the electrolyte and the cell potential is investigated using the following electrochemical cell represented by the cell notation:

Aℓ(s) | $A ℓ^{3 +}$ (aq) || $M^{2 +}$ (aq) | M(s)

The concentration of $M^{2 +}$ is changed and the corresponding emf is measured. The concentration of $A ℓ^{3 +}$ (aq) and the temperature are at standard conditions. The graph below shows the results of this investigation.
8.6 Metal M is now replaced with magnesium, Mg.
8.6.2 Refer to the relative strengths of the oxidising agents to explain the answer.(2)
Show the memo (2 ticks)Memo
1. ✓
  Compare oxidising agents $A ℓ^{3 +}$ is a stronger oxidising agent than $Mg^{2 +}$
  1 mark · Compare oxidising and reducing agent strength
2. ✓
  Conclusiontherefore, Mg will be oxidised (to $Mg^{2 +}$ ).
  1 mark · Compare oxidising and reducing agent strength
6. Question 9.3 · May/June 2024 · Paper 2 · National (DBE) · 2 marks
The simplified diagram below represents the cell used for electroplating ornaments with silver, Ag. P and Q are the two terminals of the battery.
9.3 Write down the equation for the half-cell reaction that takes place at the cathode.(2)
Show the memo (1 tick)Memo
1. ✓
  Reduction half-reaction $Ag^{+} + e^{-} \to Ag$
  2 marks · Write half-reactions
7. Question 1.9 · November 2024 · Paper 2 · National (DBE) · 2 marks
Various options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1.11 E.
1.9 A standard galvanic cell is set up, as shown below.

Which ONE of the following combinations of the metal used as cathode and the electron flow direction is CORRECT?(2)
1. A Metal used as cathode: Cd; electron flow direction: Cd to Ag
2. B Metal used as cathode: Ag; electron flow direction: Cd to Ag
3. C Metal used as cathode: Cd; electron flow direction: Ag to Cd
4. D Metal used as cathode: Ag; electron flow direction: Ag to Cd
Show the memo (1 tick)Memo
1. ✓
  Correct option $Ag^{+}$ ( $E^{θ} = + 0, 80$ V) is a stronger oxidising agent than $Cd^{2 +}$ ( $E^{θ} = - 0, 40$ V), so $Ag^{+}$ is reduced and Ag is the cathode. Cd is oxidised at the anode.
  Electrons are released at the anode and flow through the external circuit to the cathode: from Cd to Ag.
  
  Answer: B
  2 marks · Describe a galvanic cell
8. Question 9.2.4 · November 2024 · Paper 2 · National (DBE) · 2 marks
9.2 The simplified diagram below represents an electrolytic cell. The electrodes are made of carbon.

Answer the questions that follow.
9.2.4 Explain the answer to QUESTION 9.2.3 by referring to the relative strengths of the oxidising agents involved.(2)
Show the memo (2 ticks)Memo
1. ✓
  Water is a stronger oxidising agentWater/ $H_{2} O$ is a stronger oxidising agent (than $Na^{+}$ /sodium ion)
  
  OR: $Na^{+}$ /sodium ion is a weaker oxidising agent than water/ $H_{2} O$
  1 mark · Compare oxidising and reducing agent strength
2. ✓
  Water will be reducedand water/ $H_{2} O$ will be reduced.
  1 mark · Compare oxidising and reducing agent strength
9. Question 9.4 · May/June 2023 · Paper 2 · National (DBE) · 2 marks
The simplified electrolytic cell below is used to electroplate a metal spring. Zinc nitrate, $Zn(NO_{3})_{2}$ (aq), is used as an electrolyte and R is an electrode.
9.4 Explain the answer to QUESTION 9.3.2.(2)
Show the memo (2 ticks)Memo
1. ✓
  Zn2+ ions are used up $Zn^{2 +}$ ions are reduced / $[Zn^{2 +}]$ decreases.
  1 mark · Describe an electrolytic cell
2. ✓
  Replaced by oxidation of the Zn anode $Zn^{2 +}$ ions must be replaced by oxidation of the Zn electrode.
  1 mark · Describe an electrolytic cell
10. Question 8.4 · November 2023 · Paper 2 · National (DBE) · 2 marks
A cleaned pure copper strip, Cu(s), is placed in a beaker containing a colourless silver nitrate solution, $AgNO_{3}$ (aq), at $25$ °C, as shown below.

After a while, it is observed that the solution in the beaker becomes blue.
8.4 The salt bridge contains potassium nitrate, $KNO_{3}$ (aq).

Write down the FORMULA of the ion in the salt bridge that will move into the silver ion solution. Choose from $K^{+}$ (aq) or $NO_{3}^{-}$ (aq).

Give a reason for the answer.(2)
Show the memo (2 ticks)Memo
1. ✓
  Ion that moves into the silver half-cell $K^{+}$
  1 mark · Describe a galvanic cell
2. ✓
  Reason $[Ag^{+}]$ decreases.
  OR In the silver half-cell the concentration of positive ions decreases.
  OR The silver half-cell becomes negative.
  1 mark · Describe a galvanic cell

Electrochemistry Grade 12 videos

Short lessons from South African teachers first. Videos load only when you tap play, to save your data.

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