15. Basic Chemistry: Redox Reaction

• Al

• HCl

• AlCl₃

• H₂

Which of the following reactions are oxidation–

reduction reactions?

• (a)

• (b)

• (c)

• (d)

• (e)

• Reaction predicted to be

  favourable

• No reaction

• Can not be defined

• Reaction predicted to be

  favourable

• No reaction

• Can not be defined

In an alkaline battery, the following two half reactions occur. Which reaction takes place at the anode?

• Zn(s)

• MnO₂(s)

• both reaction

• no reaction happened

• can not be defined

• anode: Cd

  cathode: H₂O

• anode: NiO₂

  cathode: Cd

• anode: NiO₂

  cathode: H₂O

• anode: Cd

  cathode: NiO₂

• there's no correct answer

In basic solution, Se^2- and SO₃^2- ions react spontaneously as seen on picture. If E°_sulfite is -0.57 V, calculate E°_selenium.

• -0.22

• 0.92

• -0.92

• we can not calculate E°_selenium

• 0.22

A voltaic cell houses the reaction between aqueous bromine and zinc metal as shown in picture. if given E°_zinc is -0.74V, calculate E°_bromine.

• 2.57 V

• -2.57 V

• -1.07 V

• can not be calculated

• 1.07 V

Certain metals can be purified by electrolysis. For example, a mixture of Ag, Zn, and Fe can be dissolved so that the metal ions are present in an aqueous solution. If a solution containing these ions is electrolysed, which metal ion will be reduced to metal first?

• Ag and Zn together

• Zn
• Fe
• Ag
• All three metals cannot be reduced.

In a Galvanic Cell, the charge of anode and cathode respectively are ...............

• Anode: positive, Cathode: positive
• Anode: neutral, Cathode: neutral
• Anode: negative, Cathode: positive
• Anode: positive, Cathode: negative
• Anode: negative, Cathode: neutral