Question

14) A0.15 M aqueous solution of the weak acid HA at 25.0 °C has a pHi of 5.35. The value of Kg for HA is A) 14 10-10 B) 7.1 10-9 E) 33 104 918-10-5 D) 3.0 10-5 15) The Kg for HON is 49-10-10, What is the value of Kb for CN-? A) 49-10-24 B) 20 10-5 D) 4.9-104 9 4.0 10-6 E) 2.0 109 16) Caleulate the pOH of a 0.0827 M aqueous sodium cyanide solution at 25.0 °C. K for CN- is 49 10-10 A) 52 B) 9.3 C) 10 D) 8.8 E) 1.1 17) A Bransted-Lowry base is defined as a substance that A) decreases (H when placed in H20 B) increases [H] when placed in H20 9 acts as a proton acceptor D) increases (OH- when placed in H2O E) acts as a proton donor 18) Of the following acids A) H2SO4 is not a strong acid 9 HNO в) нсю D) HC E) HNO3 19) Which one of the following is the weakest acid? A) HNO2 (K-45 10-4) B) HCN (K-49-10-10 9 HCIO (K-3.0 10-8) D) HF (K-6.8. 10-4) E) Acetic acid (Kg-1.8 - 10-5) 20) A 0.1 M aqueous solution of will have the lowest pH at 25.0 °C NaOC KC NH4C Ca(OAch A) NaOC B) ка 9 NH4C D) Ca(OAc2 E) KCl and NHa 21) Which of the following combinations of chemicals could be used to make a buffer solution? A) HCИНРО в) HCINHS 9 NaOH/NH3 D) HCUNaOH 22) What is the pH of a solution prepared by mixing 25.00 ml. of 0.10 M CH3CO2H with 25.00 ml of 0.050 M CH3CO2Na? Assume that the volume of the solutions are additive and that Ka 1.8 10-5 for CHy CO2 H A) 474 B) 4.44 92.87 D) 5.05 A-3
Just give me the answers

Answer 1

14. Option A. Hint: pH=(pka-logC)/2

15. Option B, hint: ka X Kb=1x10^-14

17. Option C, proton Acceptor

18. Option C , HNO2

19. Option B, smllers the ka , weaker the acid

20. Option C , since it is more acidic solution, less pH

21. Option B, weak base and strong acid forms good buffer solution.

22. Option B, an acidic buffer, pH=pka+log(salt/acid)