A galvanic cell is constructed from the following two half cells under standard conditions. Half cell 1: a nickel electrode in a solution of 1.0 M nickel nitrate Half cell 2: a cadmium electrode in a solution of 1.0 M cadmium nitrate A sketch of the cell is given below. Given that the standard reduction potential of Cd 2+ (aq)/Cd(s) is -0.40 V, show on the above sketch the direction in which electrons will flow in the external circuit of this galvanic cell. Give the equation for the half reaction that takes place at the anode of this cell. List two factors that need to be considered when selecting an appropriate substance for use in the salt bridge.

SSCE VCE Chemistry Primary Galvanic Cells and Fuel Cells as Sources of Energy: A galvanic cell is constructed f

A galvanic cell is constructed from the following two half cells under standard conditions - VCE - SSCE Chemistry - Question 7 - 2008 - Paper 1

Question 7

A galvanic cell is constructed from the following two half cells under standard conditions. Half cell 1: a nickel electrode in a solution of 1.0 M nickel nitrate Hal... show full transcript

Worked Solution & Example Answer:A galvanic cell is constructed from the following two half cells under standard conditions - VCE - SSCE Chemistry - Question 7 - 2008 - Paper 1

Step 1

Given that the standard reduction potential of Cd2+(aq)/Cd(s) is -0.40 V, show on the above sketch the direction in which electrons will flow in the external circuit of this galvanic cell.

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Answer

In the galvanic cell, electrons flow from the anode (where oxidation occurs) to the cathode (where reduction occurs). Since Cd2+/Cd has a lower standard reduction potential compared to Ni2+/Ni, cadmium will be oxidized at the anode. Therefore, electrons will flow from the cadmium electrode (anode) towards the nickel electrode (cathode), indicated by arrows directed from half cell 2 to half cell 1 in the sketch.

Step 2

Give the equation for the half reaction that takes place at the anode of this cell.

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Answer

The half reaction at the anode (where oxidation occurs) can be given as:

$\text{Cd}(s) \rightarrow \text{Cd}^{2+}(aq) + 2e^-$

Step 3

List two factors that need to be considered when selecting an appropriate substance for use in the salt bridge.

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Answer

The substance must be soluble or ionic to allow for ion movement, facilitating the flow of charge between the two half cells.
The substance must not react with the electrolyte solutions in the half cells to prevent precipitate formation that could block the flow of ions.

A galvanic cell is constructed from the following two half cells under standard conditions - VCE - SSCE Chemistry - Question 7 - 2008 - Paper 1

Worked Solution & Example Answer:A galvanic cell is constructed from the following two half cells under standard conditions - VCE - SSCE Chemistry - Question 7 - 2008 - Paper 1

Given that the standard reduction potential of Cd<sup>2+</sup>(aq)/Cd(s) is -0.40 V, show on the above sketch the direction in which electrons will flow in the external circuit of this galvanic cell.

Give the equation for the half reaction that takes place at the anode of this cell.

List two factors that need to be considered when selecting an appropriate substance for use in the salt bridge.

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