Redox - exam practice

Which is a redox reaction?

The standard reduction potentials of two systems are

Sn⁴⁺_(aq) + 2e^- ⇌ Sn²⁺_(aq) E^⦵ = +0.15 V

Fe³⁺_(aq) + e^- ⇌ Fe²⁺_(aq) E^⦵ = +0.77 V

What is the value of E^⦵_cell for the system below?

Sn⁴⁺_(aq) + 2Fe²⁺_(aq) ➔ Sn²⁺_(aq) + 2Fe³⁺_(aq)

In a hydrogen-oxygen fuel cell, the oxygen is

The reaction between acidified dichromate(VI) ions, Cr₂O₇^2-, and aqueous Fe²⁺ ions results in the dichromate(VI) ions being reduced to Cr³⁺ ions.

What is the correct equation for this reaction?

The acid used in a standard hydrogen electrode to provide a 1 mol dm^-3 solution of hydrogen ions is

To measure the standard electrode potential for the Ag⁺_(aq) | Ag_(s) electrode, the most suitable chemical for the solution in a salt bridge to connect the two half cells is

An electrochemical cell consists of a standard hydrogen electrode and a Cu²⁺_(aq) | Cu_(s) electrode which uses copper(II) sulfate solution.

Which one of the following does not affect the e.m.f. of the cell?

The standard electrode potentials of two half reactions are shown below.

$\frac{1}{2}$Cl₂ + e^- ⇌ Cl^- E^⦵ = +1.36 V

Co³⁺ + e^- ⇌ Co²⁺ E^⦵ = +1.82 V

Which of the following processes is thermodynamically favourable? The reaction of

A solution of potassium manganate(VII) was used to determine the concentration of iron(II) ions in solution by titration in the presence of excess dilute sulfuric acid.

With the potassium manganate(VII) in the burette, the end-point of the reaction is when the solution in the conical flask turns

Which of the statements about a standard hydrogen electrode, for which E^⦵ = 0 V, is correct?

The table below gives the standard electrode potentials of three half cells.

From these data it may be deduced that, under standard conditions,

Which of the following statements about fuel cells is not true?

A student is given the electrode potentials below.

Cu²⁺ + 2e^- ⇌ Cu E^⦵ = +0.34 V

Ag⁺ + e^- ⇌ Ag E^⦵ = +0.80 V

The student sets up a cell from the two half cells.

Which statement is correct?

The redox equilibria for a hydrogen-oxygen fuel cell in alkaline solution are shown below.

2H₂O_(l) + 2e^- ⇌ H_2(g) + 2OH^-_(aq) E^⦵ = –0.83 V

$\frac{1}{2}$O_2(g) + H₂O_(l) + 2e^- ⇌ 2OH^-_(aq) E^⦵ = +0.40 V

What is the equation for the overall cell reaction?

The following cell has an e.m.f. of +0.46 V.

Cu | Cu²⁺ || Ag⁺ | Ag

Which statement is correct about the operation of the cell?

The values for two electrodes are shown.

Fe²⁺_(aq) + 2e^- ⇌ Fe_(s) E^⦵ = -0.44 V

Cu²⁺(aq) + 2e^- ⇌ Cu_(s) E^⦵ = +0.34 V

What is the e.m.f. of the cell Fe_(s) | Fe²⁺_(aq) || Cu²⁺_(aq)| Cu_(s)?

Which describes the flow of electrons in a voltaic cell?

Which is not a requirement of the standard hydrogen electrode (SHE)?

Where does oxidation occur in a voltaic cell?

Consider the following half-equations:

I_2(s) + 2e^- ⇌ 2I^-_(aq)

(brown) (colourless)

MnO₄^-_(aq) + 8H⁺_(aq) + 5e^- ⇌ Mn²⁺_(aq) + 4H₂O_(l)

(purple) (colourless)

Which statement is correct for the reaction between KMnO_4(aq) and KI_(aq) in acidic conditions?

A voltaic cell is constructed from zinc and copper half-cells. Zinc is more reactive than copper.

Which statement is correct when this cell produces electricity?