Consider these two acids and their K_a values. HF K_a = 3.5 times 10^-4 HCIO K_a
ID: 993517 • Letter: C
Question
Consider these two acids and their K_a values. HF K_a = 3.5 times 10^-4 HCIO K_a = 2.9 times 10^-8 Which acid is stronger? Consider these two acids and their K_a values. HF K_a = 3.5 times 10^-4 HCIO K_a = 2.9 times 10^-8 Which of these bases is stronger: F or CIO^- ? Calculate the [OH^-] for a solution with a (H_2O^+) = 1.5 times 10^-9 M. Is the solution in #15 above, acidic, basic or neutral? Calculate (H_3O^+] for a solution with a pH of 4.80. Calculate [OH^-] for a solution with a pH of 8.25. NH_4^+ behaves as a Bronsted-Lowry acid. What is its conjugate base? H_2PO_4^- can act as either an acid or a base. What term describes this ability? What is the pH of an 8.77 times 10^-3 M LiOH solution? What is the pOH of an 8.77 times 10^-3 M LiOH solution? NH_3 acts as a weak base with a K_b of 1.8 times 10^-5. What is the pH of a solution of NH_3 with a concentration of 0.025M? NH_3(aq) + H_2O (I) NH_4^+ (aq) + OH^- (aq)Explanation / Answer
13. Acid with lower pKa value is stronger.
pKa of HF = 3.45
pKa of HClO= 7.53
HF is stronger.
14. Conjugate base of weak acid is stronger, so ClO- is stronger.
15. [OH-] =pKw/[H3O+] = 10-14/1.5*10-9 = 6.67*10-6
16. pH = -log [H3O+] = 8.8 >7
so solution is basic.
17. [H3O+] = 10-4.80 = 1.58*10-5
18. pH = 8.25
pOH = 14-8.25 = 5.75
[OH-] = 10-5.75 = 1.78*10-6
19. NH3
20. Amphoteric
21. [OH-] = 8.77*10-3 M
pOH = - log[OH-] = 2.06
pH = 14-2.06 = 11.94
22. [OH-] = 8.77*10-3 M
pOH = - log[OH-] = 2.06
23. pOH of a weak base solution = 0.5(pKb - logC)
= 0.5(-log 1.8*10-5 - log0.025)
= 3.17
pH = 14-3.17 = 10.83