Answer :
According to one acid-base theory, a water molecule acts as an acid when the water molecule (3) donates an H+.
A water molecule acts as an acid when the water molecule donates an H+.
The correct option is 3, donates an H+.
What is the acid-base theory?
The Acid-base theory tells that if a substance produce hydrogen ion is called as an acid.
If the substance accepts, a hydrogen ion is called as base.
This theory is given by Arrhenius.
Thus, the correct option is 3, donates an H+.
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