more chemistry?

Question

1) what is the pH of a solution for which [H+] = 2.4 X 10^-7? is this solution acidic or basic?

2) what is the pOH of the same solution?

3) what is the pH of a 3.0 X 10^-4 solution of NaOH? is this solution acidic or basic?

4) what is the molarity of a 2548 L solution that contains 1.37 g HNO3

5) what is the pH, pOH, [OH-] and [H+] for the last problem?

Answer 1

Boy, I will tell you how to, but you are the one to do these excises. you need to specify all the units such as [H+] = 2.4 X 10^-7 (unit?). Also, you need to memorize these often-used formulae.
1. pH = - log(base10) [H+].
When pH is around 7, say between 6.5 to 7.5, the solution is neutrial.
2. pOH = 14 - pH = - log(base10) [OH-].
3. NaOH is a strong electrolyte thus completely dissociate in aquaous solution to Na+ and OH-. So [OH-] = 3.0 X 10^-4 (unit?)
4. Find the formula mass of HNO3, and then (1.37 g) / (formula mass of HNO3) is the mole of HNO3. This number devided by 2548 L becomes concentration of HNO3 in "M". Also, HNO3 is a strong acid and completely dissociate to [H+] and [NO3-].
5. [OH-] = 10^14 /[H+]. also see my hints for #1 and #2.