Sorting Metals using Standard Reduction Cell Potential

Question

The Scenario

A new chemistry teacher arrives in her new room and discovers that the room was left in total chaos by her predecessor. While organizing the room, she finds a box on a shelf in the prep room labeled "Electrochemistry demonstration". The box contains some metal strips, and a solution in a bottle. The metal is labeled "Metal E" and the solution is labeled "1 M nitrate salt of E". In an attempt to organize the activity, she looks throughout the room for similar samples. She manages to find samples of metals and their nitrate solutions labeled A, B, C and D in addition to the original sample. In a file cabinet, she finds a paper labeled "Electrochemistry Activity" which lists five metals: zinc, aluminum, magnesium, silver and tin She is not able to find anything that identifies which metals correspond to which letters. She makes some quick observations, summarized below.

1. The solution of metal "B" appears to have had ⁺³(aq) written on the label.
2. Metals A, B, C, and E, all react with dilute hydrochloric acid, metal D does not.
3. The metal labled "C" is the least dense of all these metals.

The teacher then assembles half cells of each metal with its nitrate salt solution, and connects half cells with a digital voltmeter and a salt bridge.

1. A cell composed of a Metal "C" half-cell and a Metal D half-cell produces the greatest voltage .
2. When the half-cell of Metal E is connected to half-cells of the other metals, Metals A and D are reduced while B and C are oxidized.
3. When a half-cell of Metal D is attached to a half-cell of Metal A, the voltmeter reads +0.9 V.

Determine the correct metal for each label.

Answer 1

Metal A = Tin

Metal B = Aluminum

Metal C = Magnesium

Metal D = Silver

Metal E = Zinc