What is the pH of a solution containing 0 250 M HONH_2 and 0.400 M HONH_3CI? (K_
ID: 1048890 • Letter: W
Question
What is the pH of a solution containing 0 250 M HONH_2 and 0.400 M HONH_3CI? (K_b for HONH_2 is 1.1 times 10^-8) 7.75 8.16 5.84 6.25 12 73 A 150.0 mL buffer solution containing 0.100 M hydrocyanic acid (HCN. K_a = 6.2 times 10^-10) and 0 100 M potassium cyanide (KCN) has 30.0 mL of 0.120 M KOH added to it. What is the pH of the solution after the KOH has been added? 8 73 9.00 9 21 9.29 9.42 The K_a of acetic acid is 1 76 times 10^-5 The pH of a buffer prepared by combining 50.0 mL of 1.00 M potassium acetate and 50.0 mL of 1.00 M acetic acid is 0.85 1.70 2.38 3.40 4.75Explanation / Answer
15. [HONH2] base = 0.25 M
[HONH3Cl] salt = 0.4 M
pkb = -logkb
= -log(1.1*10^-8)
= 8
pH of basic buffer = 14 - [pkb+log(salt/base)]
pH = 14-(8+log(0.4/0.25))
= 5.8
answer: C.5.84
16. no of mole of HCN added = 150*0.1 = 15 mmole
no of mole of KCN added = 150*0.1 = 15 mmole
no of mole of KOH = 30*0.12 = 3.6 mmole
pH of buffer = pka + log(salt+KOH/acid-KOH)
pka = -logka
= -log(6.2*10^-10)
= 9.2
pH = 9.2+log((150+3.6)/(150-3.6))
= 9.22
answer :C.9.21
17. from the data
no of mole of CH3COOK = 50*1 = 50 mmole
no of mole of CH3COOH = 50*1 = 50 mmole
pka = -logKa
= -log(1.76*10^-5)
= 4.75
as no of mole of CH3COOK = no of mole of CH3COOH
pH = pka = 4.75
answerr: e.4.75
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.