textbook 6b.1

[905290504]

Question: The molar concentration of HCl in hydrochloric acid is reduced to 12 percent of its initial value by dilution. What is the difference in pH values of the two solutions?

I wasn't sure how to do this and the answer manual's solution didn't make much sense to me, if someone could explain, I would really appreciate it
thanks!

[Sara_Lim_2C]

I haven't done this yet, so I'm not sure if this is right, but if I were doing this problem, I would assume a volume of 100mL of HCl or something like that, and use M1V1=M2V2 to find the molar concentration of HCl in both the original 100mL and in the diluted version. There should be 1 mol of H+ for each mole of HCl. Then use the pH=-log[H+] to find the pH of each solution.

I have no idea if that's right, but that's what my first instinct would be to try. I'm not super great at explaining things over writing, but I hope that helps a little!

[Astha Sahoo 3I]

So according to the solution manual, you just take the -log(0.12) and that gives you the answer!