When an acid reacts with a metal, what gas is produced?

When an acid reacts with a metal, what gas is produced?

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

Answer: (C)

When an acid reacts with a metal, hydrogen gas is produced. The acid supplies H+ ions, and the metal donates electrons to reduce those hydrogen ions to H2 gas, while the metal itself forms a positive ion that pairs with the acid’s anion to form a salt. Oxygen gas would come from reactions involving oxygen or oxidation by air, not from a typical acid–metal displacement. Nitrogen gas arises from processes involving nitrates or air, and carbon dioxide forms when an acid reacts with carbonate compounds, not from a simple acid–metal reaction.

When an acid reacts with a metal, hydrogen gas is produced. The acid supplies H+ ions, and the metal donates electrons to reduce those hydrogen ions to H2 gas, while the metal itself forms a positive ion that pairs with the acid’s anion to form a salt. Oxygen gas would come from reactions involving oxygen or oxidation by air, not from a typical acid–metal displacement. Nitrogen gas arises from processes involving nitrates or air, and carbon dioxide forms when an acid reacts with carbonate compounds, not from a simple acid–metal reaction.