You can't? 0.400 molar is 0.400 M.
The pH looks ok to me. 1 M HCl has pH of 0 so 0.400 M should be just a bit higher and it is.
What is the pH of a 0.400 molar HCl solution?
I did -log(.4)=.398. That seems too low. I think I need to find the molarity (M) of the solution, but I can't find it with the given information.
3 answers
Okay thank you. I didn't realize they were the same.
But in "What is the pH of a 0.300 molar NaOH solution?" -log(.3)=.523 is incorrect. Why?
But in "What is the pH of a 0.300 molar NaOH solution?" -log(.3)=.523 is incorrect. Why?
Because you calculate the pOH, not the pH. Since NaOH ==> Na^+ + OH^- then the OH is 0.3 M.
To convert from pOH to pH it is
pH + pOH = pKw = 14. Knowing pKw and either of the others, you can interchange pH ad pOH quickly and easily.
To convert from pOH to pH it is
pH + pOH = pKw = 14. Knowing pKw and either of the others, you can interchange pH ad pOH quickly and easily.