Question 1

Which of the following best describes the purpose of cathodic protection in corrosion prevention?

Accepted Answer

It uses a more active metal as the anode to protect iron from oxidation.

Question 2

A steel pipe is buried underground and connected to a magnesium rod. What is the role of magnesium in this setup?

Accepted Answer

Magnesium acts as a sacrificial anode, corroding instead of the steel.

Question 3

During the electrolysis of molten sodium chloride in a Downs cell, what are the products at the cathode and anode?

Accepted Answer

Cathode: Na(l); Anode: Cl2(g)

Question 4

Which equation correctly relates electric charge (Q), current (I), and time (t)?

Accepted Answer

$$Q = I 	imes t$$

Question 5

A current of 2.43 A flows for 10.0 minutes during the electrolysis of a nickel salt solution. How many coulombs of charge have passed?

Accepted Answer

$$2.43 	imes 600 = 1458 C$$

Question 6

Which of the following metals is more active towards oxidation than iron (Fe)?

Accepted Answer

Magnesium (Mg)

Question 7

In the electrolysis of an aqueous sodium chloride solution, which gas is produced at the anode?

Accepted Answer

Chlorine ($$Cl_2)$$

Question 8

Which statement about overpotential is correct?

Accepted Answer

Overpotential increases the voltage required for electrolysis compared to the theoretical value.

Question 9

What is the oxidation state of nickel in $$NiOOH$$?

Accepted Answer

+3

Question 10

Which of the following is a real-world application of electrolytic cells?

Accepted Answer

Production of aluminum metal

Question 11

During the electrolysis of water, which half-reaction occurs at the cathode?

Accepted Answer

$$2H_2O(l) + 2e^- \rightarrow H_2$(g) + 2OH^-(aq)$$

Question 12

Which of the following is NOT a reason for overpotential in electrochemical cells?

Accepted Answer

Increase in solution temperature

Question 13

Which of the following statements is true regarding the selection of half-cell reactions in electrolytic cells?

Accepted Answer

The reaction with the smallest (least negative) total cell potential occurs.

Question 14

A fuel cell used by NASA combines hydrogen and oxygen under basic conditions. What is the net reaction?

Accepted Answer

$$2H_2(g) + O_2$(g) \rightarrow 2H_2O(g)$$

Question 15

Calculate the standard emf ($$E_{cell}^\circ) $$for the oxygen-hydrogen fuel cell under basic conditions, given: $$2H_2O(l) + 2e^- \rightarrow H_2$(g) + 2OH^-(aq)$$, $$E^\circ = -0.83 V$$; $$O_2(g) + 2H_2O(l) + 4e$$^- \rightarrow 4OH^-(aq)$$, E$$^\circ = 0.40$$ V.

Accepted Answer

$$E_{cell}^\circ = 1.23 V$$

Question 16

Which is the stronger reducing agent under standard conditions: $$Sn^{2+} (to$$ $$Sn^{4+}) or Fe (to$$ $$Fe^{2+}$$)?

Accepted Answer

Fe (to $$Fe^{2+})$$

Question 17

Which is the stronger oxidizing agent under standard conditions: $$Cl_2 or$$ $$MnO_4$$^-$$?

Accepted Answer

$$MnO_4$$^-$$

Question 18

Will dichromate ion oxidize manganese(II) ion to permanganate ion in acid solution under standard conditions?

Accepted Answer

No, because the standard reduction potential for $$MnO_4$$^-$$ is higher than for Cr_2O$$_$$7^{2-}.$$

Question 19

If you place a battery in a flashlight in which all electrochemical reactions have reached equilibrium, what will happen when you turn on the flashlight?

Accepted Answer

The flashlight will not turn on because no net reaction occurs at equilibrium.

Electrochemistry: Electrolytic Cells, Corrosion, and Applications

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