Review :)

A redox reaction is NOT:

• all reactions

• a combustion reaction

• a reduction-oxidation reaction

• a reaction in which electrons are transferred from one atom to another

What is the oxidation number for magnesium ion?

• 0

• +2

• +1

Which compound has manganese with oxidation number +6?

Which one below is redox reaction?

The correct description about redox reaction is

• Oxygen is definitely present

• The oxidising agent itself carries out oxidation

• Oxidation takes place before reduction

• Electron transfer definitely takes place

Below shows a cell diagram for voltaic cell. Which of the following is FALSE?

• Electrons flow from anode to cathode
• Oxidation happens in anode
• Copper undergo reduction to form copper ions
• Zinc undergo oxidation to form Zinc ions

In which direction does electricity flow in a voltaic cell ?

• Electrons flow from the cathode to the anode

• Electrons flow from left to right

• Electrons flow from anode to cathode

• Electrons flow from right to left

What reaction occurs at the anode?

EAg = + 0.799 V , ENi = -0.257 V

• Ag⁺ + e^- →Ag

• Ag → Ag⁺ + e^-

• Ni²⁺ + 2e^- → Ni

• Ni → Ni²⁺ + 2e^-

Which one represent the cell notation for a zinc half-cell connected to a copper half-cell?

Zn2+ + 2e- -->  Zn , EZn = -0.7618 V

Cu2+ + 2e- --> Cu , ECu = + 0.3419 V

• Zn2+(aq) / Zn(s) || Cu(s) / Cu2+(aq)

• Zn2+(aq) / Zn(s) || Cu2+(aq) / Cu(s)

• Zn(s) / Zn2+(aq) || Cu2+(aq) / Cu(s)

• Zn(s) / Zn2+(aq) || Cu(s) / Cu2+(aq)

Explain the function of a salt bridge in a voltaic cell

• provides an electrical connection between the two half-cells to complete the circuit

• provides an pathway for electrons to flow to each of the half-cells

• allows ions to flow into or out of the half-cells to balance out the charges in the half-cells

• prevents the flow of the anions and cations from the salt used in the salt bridge to the two half-cells