Answer: hydrogen
All acids have the hydrogen ion in common
Explanation:
According to Arrhenius theory, an acid is a substance which dissociate in water to produce hydrogen ions, H+;
For example: HCl --> H+ + Cl-
while a base is a substance which gives hydroxide ions, OH-, in water
For example: NaOH(s) --> Na+(aq) + OH-(aq)
Thus, all acids have the hydrogen ion in common
