1. Carbonic Acid (H₂CO₃)

* Decomposition: H₂CO₃(aq) → H₂O(l) + CO₂(g)

* Gas formed: Carbon dioxide (CO₂)

2. Sulfurous Acid (H₂SO₃)

* Decomposition: H₂SO₃(aq) → H₂O(l) + SO₂(g)

* Gas formed: Sulfur dioxide (SO₂)

Note: Both of these decompositions occur when the acids are heated or when they are exposed to a decrease in pressure.