Other examples include amino acids and proteins, which have amine and carboxylic acid groups, and self-ionizable compounds such as water and ammonia.ExamplesZinc oxide (ZnO) reacts differently depending on the pH of the solution:In acids: ZnO + 2H+ ??? Zn2+ + H2OIn bases: ZnO + H2O + 2OH- ??? [Zn(OH)4]2-This effect can be used to separate different cations, such as zinc from manganese.There are ma