The rechargeable nickel-cadium cell is used to power small appliances such as portable computers - VCE - SSCE Chemistry - Question 7 - 2005 - Paper 1
Question 7
The rechargeable nickel-cadium cell is used to power small appliances such as portable computers. When the cell is being used, the electrode reactions are represente... show full transcript
Worked Solution & Example Answer:The rechargeable nickel-cadium cell is used to power small appliances such as portable computers - VCE - SSCE Chemistry - Question 7 - 2005 - Paper 1
Step 1
I cadmium is deposited on the negative electrode
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Answer
During the recharging process, cadmium is indeed deposited on the negative electrode. This happens because the direction of the electron flow during charging changes, causing the reduction of cadmium ions from the electrolyte, leading to their deposition on the electrode.
Step 2
II the pH of the electrolyte increases
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Answer
As the nickel-cadium cell is recharged, there is an increase in hydroxide ions (OH⁻) as cadmium is plated out. This results in a higher concentration of OH⁻ ions in the electrolyte, causing an increase in pH.
Step 3
III the direction of electron flow in the external circuit is from the anode to the cathode
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Answer
During recharging, electron flow is indeed from the anode (where oxidation occurs) to the cathode (where reduction occurs). Thus, this statement is also correct.
