Which one of the following gases gives acidic solution on dissolving i

Which one of the following gases gives acidic solution on dissolving in water?

Hydrogen
Carbondioxide
Nitrogen
Oxygen
This question was previously asked in
UPSC NDA-2 – 2016
When carbon dioxide (CO₂) dissolves in water (H₂O), it reacts to form carbonic acid (H₂CO₃) through a reversible reaction: CO₂ + H₂O ⇌ H₂CO₃. Carbonic acid is a weak acid that can dissociate into hydrogen ions (H⁺) and bicarbonate ions (HCO₃⁻), and further into hydrogen ions and carbonate ions (CO₃²⁻). The presence of hydrogen ions increases the acidity of the solution.
Non-metal oxides that react with water form acidic solutions. CO₂ is an oxide of carbon, a non-metal. Other examples include SO₂ and NO₂, which form sulfurous/sulfuric acid and nitrous/nitric acid respectively, contributing to acid rain.
Hydrogen (H₂), Nitrogen (N₂), and Oxygen (O₂) are diatomic gases that do not react with water to form acids under normal conditions. H₂ is neutral. N₂ and O₂ are relatively inert. Oxides of metals, on the other hand, typically form alkaline solutions when dissolved in water (e.g., Na₂O + H₂O → 2NaOH).