Most Important Electrochemistry MCQs with Answers

Electrolytic conduction relies on the mobility of ions, which is achieved when the electrolyte is in a molten (fused) state or dissolved in a solvent to form an aqueous solution.

Cations are positively charged ions, and in an electrolytic cell, they are attracted to and move towards the negatively charged cathode.

During the electrolysis of molten NaCl, sodium ions (Na⁺) are reduced to sodium metal (Na) at the cathode, and chloride ions (Cl⁻) are oxidized to chlorine gas (Cl₂) at the anode.

The Hall-Heroult process is a widely used electrolytic method for the large-scale production of aluminum from its ore, alumina.

The Nelson cell is an industrial electrolytic cell used for the production of caustic soda (sodium hydroxide, NaOH) and chlorine gas from brine (aqueous sodium chloride).

Anodizing is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of aluminum parts, thereby enhancing their corrosion resistance and wear resistance.

A galvanic cell is designed to convert chemical energy, released from a spontaneous oxidation-reduction reaction, into electrical energy.

The salt bridge allows for the migration of ions between the two half-cells, which maintains electrical neutrality in the solutions and completes the electrical circuit, allowing current to flow.

Zinc is oxidized at the anode (loses electrons), and these electrons then flow through the external circuit to the copper cathode, where reduction occurs.

In the zinc-copper cell, zinc metal is oxidized to zinc ions (Zn → Zn²⁺ + 2e⁻) and copper ions are reduced to copper metal (Cu²⁺ + 2e⁻ → Cu). The sum of these half-reactions gives the overall spontaneous reaction.

A galvanic cell's spontaneous reaction can be reversed by applying an external electrical potential that is greater than its own cell potential and in the opposite direction, forcing the non-spontaneous reaction to occur, thus operating as an electrolytic cell.

When a galvanic cell is reversed to act as an electrolytic cell, it consumes electrical energy to drive a non-spontaneous chemical reaction, thereby converting electrical energy into chemical energy.

The electrodes in a galvanic cell serve as the sites where the oxidation and reduction half-reactions take place, facilitating the electron transfer.

The document explicitly states that the standard cell potential of the zinc-copper galvanic cell is 1.1 V

Standard electrode potential is measured at a temperature of 298 K (25°C), with the concentration of ions in the solution being 1.0 M (and 1 atm pressure for gases).

The Standard Hydrogen Electrode (SHE) is assigned an arbitrary potential of exactly zero volts under standard conditions, serving as a universal reference point for measuring other electrode potentials.

The SHE consists of a platinum electrode immersed in a 1 M aqueous solution of H⁺ ions (e.g., HCl), with hydrogen gas at 1 atm pressure bubbled around the platinum electrode.

The potential of a single electrode cannot be measured directly. It is determined by coupling it with a standard reference electrode (like the SHE) to form a galvanic cell and then measuring the overall potential difference (voltage) of that cell.

Standard electrode potential is conventionally reported as the standard reduction potential, which indicates the tendency of a species to gain electrons (be reduced) under standard conditions.

The standard reduction potential for a half-reaction is equal in magnitude but opposite in sign to its standard oxidation potential.

The difference in electrode potentials between the two half-cells creates an electromotive force (EMF) or potential difference, which drives the flow of electrons through the external circuit.

A positive standard reduction potential signifies that the species has a greater tendency to undergo reduction (gain electrons) compared to hydrogen under standard conditions.

A negative standard reduction potential suggests that the species has a greater tendency to undergo oxidation (lose electrons) compared to hydrogen under standard conditions

The Down's cell is a specific electrolytic method used for the industrial production of sodium metal from molten sodium chloride.

While oxygen commonly has an oxidation number of -2, in peroxides, its oxidation number is -1.

Galvanic or voltaic cells are designed to generate electrical energy from spontaneous chemical (oxidation-reduction) reactions.

In a basic medium, hydrogen atoms are balanced by adding water molecules (H₂O) to the side deficient in hydrogen, and an equal number of hydroxide ions (OH⁻) to the opposite side.

The Standard Hydrogen Electrode (SHE) serves as the reference electrode, and its standard electrode potential is, by convention, set to exactly zero volts.

Anodizing is an electrolytic process that forms a thicker, more durable, and highly corrosion-resistant oxide layer on the surface of aluminum.

In oxygen difluoride (OF₂), fluorine is more electronegative than oxygen. Therefore, oxygen exhibits a positive oxidation number of +2 to balance the two -1 oxidation states of fluorine.

Electrolytic conductors are substances that conduct electricity through the movement of ions when they are in a molten (fused) state or dissolved in a solvent (aqueous solution). Fused sodium chloride fits this description.

Galvanic cells convert chemical energy into electrical energy through a spontaneous oxidation-reduction reaction that inherently proceeds without external energy input.

To determine the potential of a single electrode, it is coupled with a reference electrode (like the SHE) to create a complete electrochemical cell, and the overall potential difference (voltage) of this cell is measured.