Electrolytic cells and electrolysis Knowledge-Based Practice

Questions

1. 1.

   During the electrolysis of acidified water using inert electrodes, what is the theoretical mole ratio of hydrogen gas produced at the cathode to oxygen gas produced at the anode?

   • A) 1 : 2
   • B) 1 : 1
   • C) 2 : 1
   • D) 4 : 1
2. 2.

   During the industrial electrolytic refining of copper, which electrode configuration and process are utilized to obtain high-purity copper?

   • A) Impure copper acts as the anode and undergoes oxidation, while pure copper deposits onto the cathode through reduction.
   • B) Impure copper acts as the cathode and undergoes reduction, while pure copper dissolves from the anode through oxidation.
   • C) Pure copper acts as the anode and undergoes oxidation, while impurities deposit onto the cathode through reduction.
   • D) Pure copper acts as the cathode and undergoes oxidation, while copper ions are reduced to precipitate out of the electrolyte.
3. 3.

   What quantity of electric charge, in coulombs, must pass through an electrolytic cell to deposit 0.50 mol of solid copper from an aqueous solution containing $\text{Cu}^{2+}$ ions? (Use Faraday's constant $F = 96{,}500\text{ C}\cdot\text{mol}^{-1}$.)

   • A) 96,500 C
   • B) 48,250 C
   • C) 193,000 C
   • D) 24,125 C
4. 4.

   During the electrolysis of a concentrated aqueous solution of sodium chloride using inert electrodes, which primary substances are liberated at the cathode and the anode, respectively?

   • A) $\text{Na}(s)$ at the cathode and $\text{Cl}_2(g)$ at the anode
   • B) $\text{Cl}_2(g)$ at the cathode and $\text{H}_2(g)$ at the anode
   • C) $\text{H}_2(g)$ at the cathode and $\text{Cl}_2(g)$ at the anode
   • D) $\text{Na}(s)$ at the cathode and $\text{O}_2(g)$ at the anode
5. 5.

   Which statement correctly describes the processes and electrode polarities in an electrolytic cell?

   • A) Chemical energy is spontaneously converted into electrical energy to generate a positive cell potential.
   • B) Reduction occurs at the positive anode while oxidation occurs at the negative cathode.
   • C) An external power source drives a non-spontaneous redox reaction, with oxidation occurring at the positive anode.
   • D) Cations migrate toward the positive anode where they gain electrons during electrolysis.

Answers and step-by-step solutions appear after you finish the test.