Answer:
- Acetic acid (CH₃COOH) and hydronium ion (H₃O⁺)
Explanation:
Hello,
In this case, based on the acid-base theory which states that acids are known as H⁺ donors, if we consider the direct reaction:

It is clear that the acetic acid is the first H⁺ donor as it losses one H⁺ to turn into the acetate ion. Moreover, if we consider the inverse reaction:

It is also clear that the hydronium ion is the second H⁺ donor as it losses one H⁺ to turn into water.
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Must contain: 6 protons, 6 electrons and 12 neutrons.