The pH of a 1.25 x 10-11 M NaOH solution is:
Answers
Explanation:
HCl is a strong acid and will dissociate completely, therefore:
[H+] = 1.25 x 10-3M
pOH = -log[H+] = -log(1.25 x 10-3)
pH = 2.90 (3 points)
pOH = 14.0 - pH = 14.0 - 2.90 = 11.1 (3 points)
2. 0.0155L of a 0.505M solution of HCl is combined with 0.0482L of a 0.0175M solution of NaOH. What is the pH of the combined solution? (10 points)
0.505 moles/L * 0.0155L = 7.83 x 10-3 moles HCl (2 points)
0.0175 moles/L * 0.0482L = 8.44 x 10-4 moles NaOH (2 points)
Have and excess of HCl. The NaOH will neutralize an equivalent number of moles of HCl, leaving the following number of moles of HCl:
7.83 x 10-3 moles - 8.44 x 10-4 moles = 6.99 x 10-3 moles HCl (2 points)
Total sample volume = (0.0155 + 0.0482) = 0.0637L
Giving an HCl concentration = (6.99 x 10-3 moles/0.0637L) = 0.110M (2 points)
pH = -log(0.110) = 0.959 (2 points)
Answer:
7.
Explanation: