Answer : The correct option is, (1) an [tex]H^+[/tex] ion
Explanation :
According to the Bronsted-Lowry or acid-base concept, a substance is called as an acid if it can donate a proton and a substance is called as a base if it can accept a proton. And the substance may be a molecule or an ion.
When a water molecule acts as an acid then it can donate a proton or [tex]H^+[/tex] ion.
When a water molecule acts as a base then it can accepts a proton or [tex]H^+[/tex] ion.
Hence, the correct option is, (1) an [tex]H^+[/tex] ion
