Electrolysis and Faraday's Law - AP Chemistry

What is the function of inert electrodes in electrolysis?

Inert electrodes conduct electricity without participating in the reaction. Unreactive electrodes only transfer electrons, don't dissolve.
Identify the main product formed at the cathode in NaCl electrolysis.

Hydrogen gas (H₂) is the main product. Water reduction produces hydrogen gas at the negative electrode.
What happens to the anode in a typical aqueous electrolysis?

The anode typically dissolves into the solution. Active anodes oxidize and release metal ions into solution.
Calculate the equivalent weight of a metal with atomic weight 56 and valence 2.

Equivalent weight = $\frac{56}{2} = 28$ g/equiv. Divide atomic weight by the number of electrons transferred.
What is the unit of electric current?

The unit of electric current is amperes (A). Standard unit for measuring electrical current flow.
Identify the role of an anode in electrolysis.

An anode is the electrode where oxidation occurs. Positive electrode where electrons are lost from species.
What is the effect of increasing the concentration of electrolyte in electrolysis?

Increases the efficiency and rate of electrolysis. More ions improve conductivity and reaction kinetics.
What is the significance of 96500 coulombs in electrolysis?

96500 coulombs is the charge of 1 mole of electrons. Faraday's constant relates charge to moles of electrons.
What is the standard potential for the reduction of silver ions?

The standard reduction potential for Ag $^+$ is +0.80 V. Standard electrode potential for silver reduction reaction.
How many coulombs are required to deposit 1 mole of monovalent ion?

96500 coulombs are required. One Faraday deposits one equivalent of any substance.
State Faraday's first law of electrolysis.

The mass of substance liberated is proportional to the charge passed. More charge produces proportionally more product deposition.
Find the charge required to deposit 0.5 moles of a substance with valence 2.

Charge = $0.5 \times 2 \times 96500 = 96500$ C. Multiply moles by valence then by Faraday's constant.
What is the oxidation number change at the anode during electrolysis?

The oxidation number increases at the anode. Oxidation involves loss of electrons, increasing oxidation state.
What is the role of a diaphragm in electrolysis?

A diaphragm separates the anode and cathode to prevent mixing of products. Physical barrier prevents product recombination and contamination.
What is the oxidation state of the metal deposited at the cathode?

The oxidation state decreases as the metal is reduced. Metal cations gain electrons, reducing their oxidation state.
What is the primary factor affecting the rate of electrolysis?

The rate of electrolysis is primarily affected by the current. Higher current drives more electrons through the circuit faster.
What is the effect of electrode surface area on electrolysis rate?

Larger surface area increases the rate of electrolysis. Greater area provides more sites for electron transfer reactions.
What is the relationship between current, charge, and time?

Charge (C) = Current (A) $\times$ Time (s). Product of current and time gives total charge passed.
How does temperature affect the rate of electrolysis?

Higher temperature increases the rate of electrolysis. Heat increases ion mobility and reaction kinetics.
What is the definition of an electrolyte?

An electrolyte is a substance that produces ions when dissolved in water, conducting electricity. Ionic compounds enable current flow in aqueous solutions.
Calculate the number of moles of electrons needed to deposit 1 mole of Al.

3 moles of electrons are needed. Aluminum has +3 charge, requiring 3 electrons for reduction.
How is the equivalent weight of an element defined in electrolysis?

Equivalent weight = $\frac{\text{Atomic weight}}{\text{Valence}}$ . Atomic mass divided by oxidation state change in reaction.

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