A 5.0 M solution of HCl in water has a proton concentration of __ M?

Expert Answers
ncchemist eNotes educator| Certified Educator

We are asked to find the proton concentration of a 5 M solution of HCl in water.  Since HCl is a strong acid, we know that it completely ionizes in water.  That means that it is separated into its respective ions in solution.  The ionization of HCl is shown below.

HCl --> H+ + Cl-

Since it completely ionizes, that means that all of the HCl is converted to H+ and Cl-.  So a 5 M solution of HCl will give a solution that is 5 M in H+ and 5 M in Cl-.  So the answer is 5 M concentration of protons.