Answer:
H 2 O
Explanation:
H 2 O can act as a Brønsted-Lowry acid by donating a proton to produce its conjugate base OH - (known as the hydroxide ion). H 2 O can act as a Brønsted-Lowry base by accepting a proton to produce its conjugate acid H 3 O + (known as the oxidanium ion, or oxonium ion, or, in older textbooks as the hydronium ion (5)).