9.The pka of NH is 9.25. What is the highest pH that a buffer system composed of NH4 and NH3 will buffer at effectively? a) 13.25 b) 12.25 c) 11.25 d) 10.25 Which of the following mixtures is a buffer: a) 25mL 0.1M HF b) 25mL 0.1M HCI mixed with 25mL 0.1M NaOH. c) 25mL 0.1M NH3 mixed with 12.5mL 0.1M HCI. d) 25mL 0.1M NaF 11. The pH of LiOH was measured to be 11.53. Which of the following statements is/a a. [OH-1 3.4 x 10-3 M b. [H] [OH] c. Solution is basic. d. [H’] 2.95 x 10-12 M