How to tell something is amphoteric?

[Chem_Mod]

How can you tell that As₂O₃ or Bi₂O₃ is amphoteric? They are amphoteric because they are metalloids; however, can you figure it out by writing out a chemical equation for a reaction of these oxides with water like you can do for BaO?

[Chem_Mod]

To be amphoteric means that the oxide can react either with acid or base. In the case of As₂O₃ we have: As₂O₃ + 6HCl --> 2AsCl₃ + 3H₂O (reaction with acid) NaOH + As₂O₃ + 3H₂O --> 2Na[As(OH)₄] (reaction with base) Something similar would apply to Bi₂O₃.

[Jacob Loo 1J]

What about for other molecules that are not in a similar As₂O₃ form? How do you tell if they are amphoteric or not?

[Juskarun Cheema]

If the compound has both basic and acidic character then it will be amphoteric.

[Ann Zhang_1M]

you can check if the compound can form H3O+ or OH- when it react with others.
If the compound can produce both when reacting with different reactants, it is amphoteric.