Problem 110 - Chemistry An Atoms First Approach

Question

What reaction will take place at the cathode and the anode when each of the following is electrolyzed? a. molten KF b. molten \(\mathrm{CuCl}_{2}\) c. molten \(\mathrm{MgI}_{2}\)

Step-by-Step Solution

Answer

a. In molten KF, potassium (K) metal is produced at the cathode, and fluorine (F₂) gas is produced at the anode. b. During the electrolysis of molten CuCl₂, copper (Cu) metal is produced at the cathode, and chlorine (Cl₂) gas is produced at the anode. c. During the electrolysis of molten MgI₂, magnesium (Mg) metal is produced at the cathode, and iodine (I₂) gas is produced at the anode.

Step 1: a. Molten KF

In molten KF, there are potassium (K⁺) and fluoride (F⁻) ions. At the cathode (reduction): K⁺ + e⁻ -> K At the anode (oxidation): 2F⁻ -> F₂ + 2e⁻ Therefore, during the electrolysis of molten KF, potassium metal is produced at the cathode, and fluorine gas is produced at the anode.

Step 2: b. Molten CuCl₂

In molten CuCl₂, there are copper (Cu²⁺) and chloride (Cl⁻) ions. At the cathode (reduction): Cu²⁺ + 2e⁻ -> Cu At the anode (oxidation): 2Cl⁻ -> Cl₂ + 2e⁻ During the electrolysis of molten CuCl₂, copper metal is produced at the cathode, and chlorine gas is produced at the anode.

Step 3: c. Molten MgI₂

In molten MgI₂, there are magnesium (Mg²⁺) and iodide (I⁻) ions. At the cathode (reduction): Mg²⁺ + 2e⁻ -> Mg At the anode (oxidation): 2I⁻ -> I₂ + 2e⁻ During the electrolysis of molten MgI₂, magnesium metal is produced at the cathode, and iodine gas is produced at the anode.