Textbook 6b1

[Ethan Goode 2H]

6B.1 The molar concentration of HCl in hydrochloric acid is reduced to 12% of its initial value by dilution. What is the difference in the pH values of the two solutions?
How do you do this problem? I am confused where to start.

[Stuti Pradhan 2J]

The easiest way to do this problem is to simply choose a molar concentration of HCl and find the pH. Then, take 12% of that molar concentration and find the pH value. Subtract the values to find the difference in pH.

For example, I used a 0.5 M solution of HCl, and then a 0.06 M solution (which is 12% of 0.5M), found the two pHs and then found the difference between them.

Hope this helps!

[Catie Donohue 2K]

I couldn't find the solution for this in the textbook - would the correct answer be ~0.921?

[Sofia Lombardo 2C]

The way I approached this problem was to use . So 0.12 [HCl] - [HCl] and then I took the -log of this value and divided by the initial [HCL] (because it is property of log functions) and then the [HCl] would cancel and I was left with just -log(0.12).

[Eric Cruz 2G]

For this problem I used 1M concentration as the original. Therefore, if you put it in the -log(H) equation, you get 0. 12% of 1M is 0.12M, so I put 0.12 in the -log(H) equation as well and got me 0.92 . I took the difference of the two which is merely just 0.92