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At the start of the day, a student set up a galvanic cell using two electrodes: nickel, Ni, and metal X - VCE - SSCE Chemistry - Question 5 - 2019 - Paper 1
Question 5
At the start of the day, a student set up a galvanic cell using two electrodes: nickel, Ni, and metal X. This set-up is shown in the diagram below. Consider the fol... show full transcript
Worked Solution & Example Answer:At the start of the day, a student set up a galvanic cell using two electrodes: nickel, Ni, and metal X - VCE - SSCE Chemistry - Question 5 - 2019 - Paper 1
Step 1
Consider the properties of the metals
Answer
To identify which metals could be used to replace metal X and lead to a darker green solution, we need to consider the reactivity and electrode potentials of the metals listed: zinc (Zn), lead (Pb), cadmium (Cd), and copper (Cu). Nickel is already being used in Half-cell 1, so we need to determine the potential reactions based on standard electrode potentials.
Step 2
Evaluate metal alternatives
Answer
The darker green solution suggests a more intense formation of nickel ions, which could occur if the replacement metal has a higher tendency to oxidize than nickel. Among the options:
- Zinc (Zn) is more reactive than nickel and can displace it, allowing nickel ions to form, resulting in a darker solution.
- Lead (Pb) is less reactive than zinc but can also interact with nickel ions positively.
- Cadmium (Cd) is more reactive than nickel and can lead to similar ion formation.
- Copper (Cu) is less reactive than nickel; hence, it will not facilitate a darker solution.
Thus, metals 1 (zinc), 2 (lead), and 3 (cadmium) can be considered as replacements.
Step 3