ElectroChemistry Quiz for IBHL

What is a redox reaction?

• A reaction where both reactants get reduced.

• A reaction where both reactants get oxidized.

• A reaction that involves a transfer of electrons between reactants.

• A reaction that involves the combustion of at least one reactant.

What is reduction?

• It is the gain of electrons.

• It is the loss of electrons.

• It is the creation of electrons.

• It is the destruction of electrons.

What is oxidation?

• It is the gain of electrons.

• It is the loss of electrons.

• It is the creation of electrons.

• It is the destruction of electrons.

Consider this cell.

Click all true statements

• Zinc will be oxidised

• Copper will be oxidised

• Electrons will flow from right to left

• The Zinc electrode is the negative electrode

• Zn²⁺ will be reduced

Consider this cell.

Select all true statements

• Zinc is a more reactive metal than copper

• Cu²⁺ is a stronger oxidising agent that Zn²⁺

• The cell potential is the sum of the two electrode potentials

• The copper electrode will get bigger as current flows

• The zinc electrode will get smaller as current flows

Answer explanation

The cell potential is the difference between electrode potentials

Copper metal will be formed from copper ions, while zinc metal will be oxidised into zinc ions.

Which is the correct definition of 'Standard Electrode Potential'?

• the e.m.f. of a half-cell connected to a standard hydrogen electrode, measured at 298K with solution concentrations of 1 moldm^-3 and gas pressures of 100kPa

• the e.m.f. of a half-cell connected to a platinum electrode, measured at 298K with solution concentrations of 1 moldm^-3 and gas pressures of 100kPa

• the e.m.f. of a half cell connected to a platinum electrode, measured at 298K with solution concentrations of 1 moldm^-3 and gas pressures of 100kPa and a voltmeter set at 1.00V

• the e.m.f. of a half-cell connected to a standard hydrogen electrode, measured at 298K with solution concentrations of 1 moldm^-3 and gas pressures of 100kPa and a voltmeter set at 1.00V

Answer explanation

The hydrogen electrode uses platinum metal to carry charge between H⁺ and H₂

Because the electrode potential of the standard hydrogen electrode is zero, the the voltmeter will show the standard electrode potential of the other half-cell.

Electrons always flow from

• cathode to anode

• anode to cathode

Given their standard reduction potentials, which of the species is going to be oxidized?

Cu²⁺/Cu = 0.34V

Zn²⁺/Zn = -0.76V

• Cu

• Zn

• CuSO4

• ZnSO4

What reaction occurs at the anode?

Ag⁺/Ag = 0.80V

Ni²⁺/Ni = -0.25V

• Ag⁺ + e^- →Ag

• Ag → Ag⁺ + e^-

• Ni²⁺ + 2e^- → Ni

• Ni → Ni²⁺ + 2e^-

What is the oxidation number of oxygen in water?

• -1

• -2

• 0

• +1

• +2