Two standard galvanic cells are shown below - VCE - SSCE Chemistry - Question 11 - 2009 - Paper 1
Question 11
Two standard galvanic cells are shown below.
On the basis of the polarity of the electrodes shown above, which one of the following reactions would not be expected ... show full transcript
Worked Solution & Example Answer:Two standard galvanic cells are shown below - VCE - SSCE Chemistry - Question 11 - 2009 - Paper 1
Step 1
A. Co^2+(aq) + Cd(s) → Co(s) + Cd^2+(aq)
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Answer
This reaction involves the reduction of Co^2+ ions and oxidation of Cd, which is plausible based on the electrode polarities.
Step 2
B. 2Mn^3+(aq) + Cd(s) → 2Mn^2+(aq) + Co^2+(aq)
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Answer
In this reaction, Mn^3+ ions are reduced and Cd is oxidized, which can occur spontaneously given suitable conditions.
Step 3
C. 2Mn^2+(aq) + 2Cd(s) → 2Mn^2+(aq) + 2Cd(s)
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Answer
This equation is not a valid redox reaction as there is no change observed; hence, it cannot proceed spontaneously.
Step 4
D. 2Mn^2+(aq) + Co^2+(aq) → 2Mn^2+(aq) + Co(s)
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Answer
This reaction implies the reduction of Co^2+ to Co, while Mn^2+ remains unchanged. Due to the electrode polarities, this reaction would not be expected to occur spontaneously.
