Exam 2A, Spring 2001

1. Complete and balance the following acid/base reactions. Label the acid, base, conjugate acid, and conjugate base for each reaction.

a. Ba(OH)₂(aq) + HCl(aq)

b. C₆H₅COOH(aq) + H₂O(l)

c. HClO₄(aq) + H₂O(l)

d. HN₃(aq) + NH₃(aq)

2. Find the pH, pOH, [H₃O⁺], and [OH^–] for the following solutions at 25 °C.

a. 0.0048 M hydroiodic acid.

b. 6.2×10^–5 M strontium hydroxide

c. A hydrofluoric acid solution with pH = 2.79

3. Indicate the stronger acid in each pair. Explain your reasoning in 5 words or less. For the stronger acid, write out the balanced reaction of the acid with water.

a. HNO₃ vs. H₂SeO₄

b. H₂Se vs. H₂S

c. H₃PO₄ vs. HSeO₃^–

4. Find the pK_a for hyponitrous acid, H₂N₂O₂, given that a 0.0039 M solution is 0.48 % ionized.

5. Find the pH of a 0.0055 M solution of ammonium ion, NH₄⁺.

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