How to calcuate therotical pH
1.) 0.1 M HCl measured pH=1
2.) 0.1 M NaOH measured pH=13?
I've responded to this also. If you can't find it I'll look and send you a link.
Hi, I don't think that's what my teacher wants
We did a lab experiement where for tube one used 9 drops of deionized water and places 1 drop of 0,1 M HCl measuring a pH= 1
2.In tube 3 used 9 drops of deionized water and placed 1 drop of 01M NaOH measuring a pH= 13
Not sure if this makes a differences he wants us to figure the dilution and pH
Unless I'm making this harder than it needs to be.
You didn't have any of that information in the first post and I'm not sure I understand what you want now. However, if you took 1 drop of 0.1 M HCl and diluted it with 9 drops of DI water the concn of HCl in the diluted solution is 0.1 M HCl x (1 drop/10 drops total) = 0.01 M HCl and you should have measured closer to a pH of 2 for the dilute solution and 1 for the initial solution.
Same comment about the diluted NaOH solution. It should be
(NaOH) = 0.1 M x (1 drop/10 drops total) = 0.01 M NaOH or pOH of 2 and you should have measured a pH of 12 for the diluted solution or 13 for the initial solution.
Did you use pH paper, universal indicator, or pH meter to measure the pH. Did you measure the pH of the diluted solution or the initial solution (or both)?
Sorry. We were give a pH indicator where we put a drop of it in the HCl and NaOH where we were able to determine the pH because HCl was a red color while NaOH was a indigo/bluish color.
My teacher didn't go over theoretical calculate pH and its not in the book but he gave this to us to do over the weekend.
OK. My guess is that "theoretical pH) means to calculate what you think it should be based on the dilution of the original 0.1 M solutions. In that case you go with the 0.1 M HCl x (1/10) = 0.01 M HCl for HCl and theoretical pH of 2 and
0.1 M NaOH x (1/10) = 0.01 M NaOH for theoretical pH of 12.
The indicator you used probably was universal indicator and your prof probably wants you to see the difference between what those dyes measure and what you calculated. As measuring devices indicators are not as good as pH meters.
To calculate the theoretical pH of a solution, you need to know the concentration of the substance in question and whether it is an acid or a base.
For the given examples:
1.) 0.1 M HCl measured pH = 1:
HCl is hydrochloric acid, which is a strong acid. Strong acids fully dissociate in water, so the concentration of H+ ions in the solution is equal to the concentration of HCl. In this case, the concentration is 0.1 M.
The pH scale is a logarithmic scale that represents the concentration of H+ ions in a solution. The formula to calculate pH is:
pH = -log[H+]
Using the given concentration:
pH = -log(0.1) ≈ 1.0
So, the theoretical pH of a 0.1 M HCl solution is approximately 1.
2.) 0.1 M NaOH measured pH = 13:
NaOH is sodium hydroxide, which is a strong base. Strong bases also fully dissociate in water to give OH- ions. In this case, the concentration of OH- ions is equal to the concentration of NaOH, which is 0.1 M.
The pOH scale is used to represent the concentration of OH- ions, and it is related to pH by the formula:
pOH = -log[OH-]
To convert pOH to pH, we can use the relationship:
pOH + pH = 14
Using the given concentration:
pOH = -log(0.1) ≈ 1.0
pH = 14 - pOH
pH = 14 - 1 ≈ 13
So, the theoretical pH of a 0.1 M NaOH solution is approximately 13.