What gas is produced when carbonate ions react with acid?

What gas is produced when carbonate ions react with acid?

• A. Carbon dioxide
• B. Hydrogen
• C. Oxygen
• D. Methane

Answer: (A)

When carbonate ions meet an acid, the carbonate is protonated to form carbonic acid, which then breaks down to carbon dioxide and water. The overall process is CO3^2- + 2H+ → CO2 + H2O, so the gas that escapes is carbon dioxide. This fizzing is a telltale sign of CO2 being released. For example, a carbonate like CaCO3 reacting with hydrochloric acid gives CaCl2, CO2, and H2O. The other gases listed aren’t produced in this reaction because it doesn’t create hydrogen gas, oxygen, or methane—those would come from different reactions.

When carbonate ions meet an acid, the carbonate is protonated to form carbonic acid, which then breaks down to carbon dioxide and water. The overall process is CO3^2- + 2H+ → CO2 + H2O, so the gas that escapes is carbon dioxide. This fizzing is a telltale sign of CO2 being released. For example, a carbonate like CaCO3 reacting with hydrochloric acid gives CaCl2, CO2, and H2O. The other gases listed aren’t produced in this reaction because it doesn’t create hydrogen gas, oxygen, or methane—those would come from different reactions.