Question

When does water act as an acid and a base?

Water can donate a proton to become a hydronium ion or hydroxide ion.

Water can accept a proton to become a hydronium ion, or donate a proton to become a hydroxide ion.

Water can accept a proton to become a hydronium ion or a hydroxide ion.

Water can donate a proton to become a hydronium ion, or accept a proton to become a hydroxide ion.

Answer 1

I believ it is B. A water molecule donates a proton. I hope this helps

Answer 2

I believe the answer is B. Water can accept a proton to become a hydronium ion, or donate a proton to become a hydroxide ion.
When water accept aproton, it will create this equation:
H2O + H+ -> H3O+ . . . . (H3O+ is the hydronium ion)

When water donate proton. it will create this chemical equation:
H2O -> H+ + OH- . . . . . . (OH- is the hydroxide ion)