Classification of Reactions

Question 1

Oxidation and Reduction

Answer 1

Oxidation is the loss of electrons by a species, whereas reduction is the gain of those electrons by another species. Because electrons cannot simply disappear, every oxidation must be matched by a simultaneous reduction. The paired processes jointly conserve both charge and mass in a redox reaction.

Question 2

Voltaic Cell Definition

Answer 2

A voltaic (galvanic) cell is a device that converts the free‑energy decrease of a spontaneous redox reaction into electrical work. It physically separates the oxidation and reduction half‑reactions into different compartments linked by an external wire and a salt bridge. Electron flow through the wire provides usable current.

Question 3

Predicting Spontaneity of Redox Reactions

Answer 3

A positive standard cell potential means ΔG° = −nFE° is negative, so the reaction is spontaneous under standard conditions. If E°₍cell₎ is negative the reaction proceeds spontaneously in the opposite direction. You can also compare K>1 when E° is positive because ΔG° = −RTlnK.