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Redox and electrochemistry — Question 24

QCAA 2023, Paper 1 · 5 marks

Q24 · 2023 · Paper 1Unclassified5 marks

QUESTION 24 (5 marks)

R and Q are unknown transition metals from period 4 of the periodic table. Pieces of R and Q were placed separately into four 0.1 M aqueous solutions. The results are shown.

Unknown metal

0.1 M aqueous solution
Zn(NO3)2
Mg(NO3)2
Cu(NO3)2
AgNO3

R

Coating

No coating

Coating

Coating

Q

No coating

No coating

Coating

Coating

A second experiment was conducted to determine the potential difference produced by electrochemical cells constructed using metals R and Q as the electrodes.

Electrochemical cell

Cathode

Anode

Voltage (V)

1

Q

R

+ 0.94

2

R

Q

− 0.94

Determine the identity of metals R and Q. Explain your reasoning.

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