Electrochemical cells (1) (AHL) questions
Assignment: Questions on Topic 19.1: Electrochemical cells (1) AHL - Standard electrode potentials
This page of questions can be marked as direct student access either for assigning as a test or for students to work on in their own time. If you do not wish to use student access, links to downloadable versions of the questions and, separately the worked answers, can be found at Printable versions of written tasks.
Consider a cell made up from the following two half-cells:
Ni2+(aq) + 2e– ⇌ Ni(s) E⦵= – 0.26 V
Ag+(aq) + e– ⇌ Ag(s) E⦵ = + 0.80 V
i. Deduce the spontaneous reaction that will occur when the cell is operating.
ii. Identify the positive and negative electrodes of the cell.
iii. Identify the species that is being oxidised and the species that is being reduced.
iv. Deduce the overall cell potential under standard conditions.
v. Calculate the Gibbs energy change for this reaction at standard conditions.
Deduce the equation for the spontaneous reaction that occurs when a dichromate half-cell, Cr2O72−(aq),H+(aq)/Cr3+(aq),H2O(l), comes into contact with an iodine half-cell, ½I2(l)/I–(aq).
Use standard redox potentials to show whether tin(II) ions can reduce iron(III) ions.
(Given: Sn4+(aq)/Sn2+(aq) E⦵ = + 0.15 V)
Show that when copper(I) salts come into contact with water they undergo disproportionation. That is, they are spontaneously oxidized and reduced at the same time.
Draw a labelled diagram of a cell made up from a Mg(s)/Mg2+(aq) half-cell connected to a Mn(s)/Mn2+(aq) half-cell operating under standard conditions.
Show the direction of electron flow in the external circuit and deduce the potential of this cell in volts.
(Upload your answer as an image or as a pdf file.)