|MadSci Network: Chemistry|
HCl is considered an acid. When HCl dissolves in water it dissociates, that is, it splits into the ions H+ and Cl-. H+ in solution is what makes an acid act like an acid.
H+ is a positive hydrogen ion. A normal hydrogen atom is made of one proton and one electron. To make the H+ Ion the electron is removed, leaving only the proton. So an H+ ion is simply a proton.
So increasing the number of protons in a solution has the same effect as adding more acid.
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