Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Help on pH problems, 10th grade chemistry?
The question is: a solution is prepared using 15.0 mL of 1.0 M HCl and 20.0 mL of 0.50 M HNO3. The final volume of the solution is 1.25 L. What are the [H+] and [OH-] in the final solution?
Thanks!!
2 Answers
- FrankieLv 51 decade agoFavorite Answer
HCl and HNO3 are both strong acids so they both ionize completely.
M = moles of solute / Liters of solution
For HCl, 1M * .015L = .015mol H+
For HNO3, .5M * .02L = .01mol H+
.01mol + .015mol = .025 mol H+
.025mol H+ / 1.25L = .02M H+
-log (.02) = 1.70 pH
pH + pOH = 14
14 - 1.7 = 12.3 pOH
10^(-12.3) = 5.01 x 10^-13 = [OH-]
- Robert SLv 61 decade ago
15.0 ml of 1.0M HCl = 0.015 moles H+
20.0 ml of 0.50 M HNO3 = 0.01 moles H+
so we have 0.025 moles of H+ in 1.25 litres
which is 0.025 / 1.25 = 0.02 M H+ ions
Concentartion of H+ = 0.02 or 2.0 x 10^-2
(pH of solution = 1.7)
pOH = 14 - pH
pOH = 14 - 1.7 = 12.3
concentration (OH-) is 5.01 x 10^-13