1. Calculate [OH−] for a solution formed by adding 5.00 mL of0.120 M KOH to 20.0 mL of 7.1×10−2 M Ca(OH)2.
2. Calculate pH for a solution formed by adding 5.00 mL of 0.120M KOH to 20.0 mL of 7.1×10−2 M Ca(OH)2.
3. Pyridine is a weak base that is used in the manufacture ofpesticides and plastic resins. It is also a component of cigarettesmoke. Pyridine ionizes in water as follows:
C5H5N+H2O⇌C5H5NH++OH−
The pKb of pyridine is 8.75. What is the pH of a 0.430Msolution of pyridine?
4. Benzoic acid is a weak acid that has antimicrobialproperties. Its sodium salt, sodium benzoate, is a preservativefound in foods, medications, and personal hygiene products. Benzoicacid dissociates in water:
C6H5COOH⇌C6H5COO−+H+
The pKa of this reaction is 4.2. In a 0.79 Msolution of benzoic acid, what percentage of the molecules areionized?
