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A student is planning to set up a demonstration of a galvanic cell using half cells constructed as follows - VCE - SSCE Chemistry - Question 7 - 2004 - Paper 1
Question 7
A student is planning to set up a demonstration of a galvanic cell using half cells constructed as follows. - Half cell 1: a calcium electrode in a beaker containin... show full transcript
Worked Solution & Example Answer:A student is planning to set up a demonstration of a galvanic cell using half cells constructed as follows - VCE - SSCE Chemistry - Question 7 - 2004 - Paper 1
Step 1
A. solid calcium (Ca) will react directly to reduce water to hydrogen gas.
Answer
Calcium is a highly reactive alkali earth metal that can react with water, producing hydrogen gas and calcium hydroxide. This direct reaction would interfere with the functioning of the galvanic cell since it would lead to reaction products that need to be considered in the system.
Step 2
B. there is no solid tin (Sn) in the half cell containing Sn⁴⁺(aq) and Sn²⁺(aq).
Answer
A galvanic cell requires solid metal to act as an electrode. The absence of solid tin means that the cell cannot sustain the redox process effectively, as there is no metallic form of tin to participate in electron transfer.
Step 3
Step 4
D. Sn⁴⁺(aq) will be in contact with Ca and will oxidise it to Ca²⁺(aq).
Answer
In a galvanic cell, a more positive reduction potential substance will oxidize the less positive one. Sn⁴⁺ has a higher tendency to gain electrons compared to elemental calcium, which leads to the oxidation of calcium to Ca²⁺.