Question

Which of the following is amphoteric?
H20
H30-
H+
O2-

Answer 1

H20

Both NH3 and H2O are amphoteric (they have H atoms that can be donated as H+ ions and thus act as acids and lone-pair electrons that can accept an H+ and thus act as bases). Thus, either NH3 or H2O can act as an acid or a base.

Answer 2

the answer is H20

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