What is the equation for chlorine gas production from halide ions?

The equation for chlorine gas production from halide ions is expressed as 2Cl⁻ → Cl₂ + 2e⁻. This equation illustrates the process of oxidation where two chloride ions (Cl⁻) lose electrons (2e⁻) and combine to form chlorine gas (Cl₂).

In electrochemical terms, halide ions are typically oxidized at the anode during electrolysis. When two chloride ions oxidize, they release two electrons and form a diatomic chlorine molecule. The factor of "2" in front of Cl⁻ indicates that two chloride ions are required for the formation of one molecule of chlorine gas, which is a fundamental concept in chemical reactions involving diatomic elements.

Understanding the charges involved is key: the chloride ions are negatively charged (Cl⁻), and when they lose electrons, they become neutral chlorine molecules (Cl₂). This reflects the principle of charge conservation in chemical reactions, where the total charge before and after the reaction must balance.

The other options do not accurately represent this oxidation process involving halide ions and the generation of chlorine gas, either including incorrect electronic balances or not appropriately using the halide ions in the reaction.