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Which oxides are exceptions that do not form oxyacids when they react with water?
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oxyacid
The structure of phosphorous acid, H3PO3.
While most nonmetal oxides react with water to form oxyacids, there are notable exceptions that do not undergo this reaction. These include:
- Carbon monoxide (CO)1
- Nitrous oxide (N₂O)1
- Nitric oxide (NO)1
Additionally, certain other oxides, such as silicon dioxide (SiO₂) and aluminum oxide (Al₂O₃), are also noted as nonreacting with water.2
It is important to distinguish these from acidic oxides that do form oxyacids. While most nonmetal oxides are acidic, some react with water through a disproportionation reaction—where the nonmetal is simultaneously oxidized and reduced—rather than simple hydration. Furthermore, while many metal oxides react with water, they typically form bases (hydroxides) rather than oxyacids.342