VHCC DE Chemistry_Unit 12_Electrochemistry_Review

The ionic equation shows the reaction between zinc (Zn) and hydrochloric acid.

Zn + 2H⁺ -> Zn²⁺ + H₂

What change takes place in the zinc?

• It gains electrons

• Its oxidation state increases

• It is reduced

• It gains hydrogen

What element is being Oxidized?

• N
• H
• O
• S

What element is being Reduced?

• N
• H
• O
• S

What is oxidation number of H in H₂O?

• 0
• -2
• -1
• +1

What is oxidation number of Cr in Cr₂O_7^2-?

• -2
• +2
• +6
• +12

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^-

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 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.

What is a cathode?

• It is the electrode where oxidation takes place.

• It is the electrode where reduction takes place.

• It is an aqueous solution containing an electrode.

• It is the salt bridge that connects half-cells.

Electrons always flow from

• cathode to anode

• anode to cathode