Deck 9: Acidûbase Equilibria

Question 1

K_a = 6.6´10^-4 for the reaction:
HF + H₂O H₃O⁺ + F^-
What is K_b for the reaction?
F^- + H₂O HF + OH^-

A) 6.6´10^-4
B) 1.6´10⁴
C) 6.6´10^-18
D) 1.5´10^-11

Answer 1

1.6´10⁴

Question 2

Which of the following is the titration curve of strong acid being titrated by a strong base

A)

B)

C)

D)

Answer 2

Question 3

Which of the following is the titration curve of weak base being titrated by a strong acid

A)

B)

C)

D)

Answer 3

Question 4

A student has 100.0 ml of 0.65 M HCl. What is the pH of this solution?

A) 1.39
B) 0.187
C) 6.50
D) 13.8
E) None of the above

Question 5

A student has 50.0 ml of 0.30 M NaOH. What is the pH of this solution?

A) 1.82
B) 11.00
C) 0.523
D) 2.0
E) None of the above

Question 6

Based on the plot below, estimate the value of K_a for the weak acid.

A) 4.7
B) 2.0´10^-5
C) 2.6
D) 2.5´10^-3
E) None of the above

Question 7

A student dissolves 30.00 grams of sodium acetate in exactly one liter of water. What will be the pH of the resulting solution?

A) 9.68
B) 9.24
C) 9.16
D) 4.84

Question 8

pertain to a solution made by combining benzoic acid and sodium benzoate. The final volume of the solution is 1.00 L and the initial concentrations of benzoic acid and sodium benzoate are 0.50 and 0.70 respectively.


-Refer to Exhibit 15-3. When adding strong acid to this solution:

A) the benzoic acid concentration should rise and the benzoate concentration should fall
B) the benzoic acid concentration should fall and the benzoate concentration should rise
C) both benzoic acid and sodium benzoate concentrations should fall
D) the concentration of all ions should remain roughly constant
E) None of the above

Question 9

pertain to a solution made by combining benzoic acid and sodium benzoate. The final volume of the solution is 1.00 L and the initial concentrations of benzoic acid and sodium benzoate are 0.50 and 0.70 respectively.


-Refer to Exhibit 15-3. Calculate the pH after the addition of an additional 250 ml of 1.00 M HCl.

A) 0.339
B) 1.54
C) 2.98
D) 5.38
E) None of the above

Question 10

pertain to a solution prepared by combining 1.0 mole of ammonia and 50.0 grams of ammonium nitrate in enough water to give a final volume of 2.00 liters.


-Refer to Exhibit 15-4. When adding strong acid to this solution:

A) the ammonia concentration should rise
B) the ammonium ion concentration should fall
C) both a and b
D) None of the above

Question 11

Which of the following titration curves schematically represents a diprotic acid being titrated by a strong base?

A)

B)

C)

D)
E) None of the above