APCE Electrochemistry

Question 1

What is the definition of oxidation in a redox reaction?

Accepted Answer

Loss of electrons.

Answer

In a redox (reduction-oxidation) reaction, oxidation is defined as the loss of electrons by a chemical species. This process results in an increase in the oxidation state of the atom or ion undergoing oxidation. A common mnemonic is OIL RIG: Oxidation Is Loss (of electrons).

Question 2

What is reduction in a redox reaction?

Accepted Answer

Gain of electrons.

Answer

Reduction in a redox reaction is defined as the gain of electrons by a chemical species. This process leads to a decrease in the oxidation state of the atom or ion undergoing reduction. The mnemonic OIL RIG helps remember this: Reduction Is Gain (of electrons).

Question 3

What does the electrode potential indicate?

Accepted Answer

The tendency of a substance to gain or lose electrons.

Answer

The electrode potential indicates the tendency of a substance to either gain electrons (be reduced) or lose electrons (be oxidized). A higher positive reduction potential signifies a greater tendency for reduction, while a more negative reduction potential indicates a greater tendency for oxidation. This value is crucial for predicting the spontaneity of redox reactions.

Question 4

What is the role of a salt bridge in an electrochemical cell?

Accepted Answer

To allow ion exchange and maintain electrical neutrality.

Answer

In an electrochemical cell, a salt bridge connects the two half-cells, allowing for the migration of ions between them. Its crucial role is to maintain electrical neutrality in each half-cell by balancing the charge buildup that occurs as electrons flow. This ion exchange completes the electrical circuit, enabling continuous electron flow.

Question 5

What is the standard electrode potential for the hydrogen ion (H⁺) half-cell?

Accepted Answer

0.00 V.

Answer

The standard electrode potential for the hydrogen ion (H⁺) half-cell, also known as the Standard Hydrogen Electrode (SHE), is conventionally assigned a value of 0.00 V. This serves as the reference point against which the electrode potentials of all other half-cells are measured and compared. It allows for the determination of relative tendencies for reduction or oxidation.

AP Practice Test

AP Practice Test

APCE Electrochemistry