CHEM 134 CH:17 (ADDITIONAL ASPECTS OF AQUEOUS EQUILIBRIA) QUESTIONS WITH COMPLETE SOLUTIONS

CHEM 134 CH:17 (ADDITIONAL ASPECTS OF AQUEOUS
EQUILIBRIA) QUESTIONS WITH COMPLETE SOLUTIONS
1) The pH of a solution that contains 0.818 M acetic acid (Ka = 1.76 ×
10^-5) and 0.172 M sodium
acetate is __________. The Ka of acetic acid is 1.76 ×10^-5
.
A) 4.077
B) 5.432
C) 8.568
D) 8.370
E) 9.922 Ans✓✓✓ A


2) Which one of the following pairs cannot be mixed together to form a
buffer solution?
A) NH3, NH4Cl
B) NaC2H3O2, HCl
C) RbOH, HBr
D) KOH, HF
E) E) H3PO4, KH2PO4 Ans✓✓✓ C


3) What change will be caused by addition of a small amount of HCl to a
solution containing fluoride
ions and hydrogen fluoride?

, A) The concentration of hydronium ions will increase significantly.
B) The concentration of fluoride ions will increase as will the
concentration of hydronium ions.
C) The concentration of hydrogen fluoride will decrease and the
concentration of fluoride ions
will increase.
D) The concentration of fluoride ion will decrease and the concentration
of hydrogen fluoride will
increase.
E) The fluoride ions will precipitate out of solution as its acid salt.
Ans✓✓✓ D


4) The Henderson-Hasselbalch equation is __________.
A) [H+] = Ka + [base]/[acid]
B) pH = pKa - log [base]/[acid]
C) pH = pKa + log [base]/[acid]
D) pH = pKa + log [acid]/[base]
E) pH = log [acid]/[base] Ans✓✓✓ C


5) The Ka of acetic acid is 1.7 x 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
__________.
A) 1.70
B) 0.85