Tuesday, February 14th Although the acid-dissociation constant for phenol (C6H5OH) is listed in your book, the dissociation constant for the phenolate ion (C6H5O-) is not. Explain why it is not necessary to list both. The Ka for phenol is 1.3 x 10-10. Calculate the Kb for the phenolate ion. Is the phenolate ion a weaker or stronger base than ammonia? (Kb for ammonia = 1.8 x 10-8) Which is more likely to occur – the acid-dissociation of phenol or base- dissociation of phenolate? Explain.

Given that Ka for acetic acid is 1 Given that Ka for acetic acid is 1.8 x 10-8 and the Ka for hypochlorous acid is 3.0 x 10-8 Which is the stronger acid? Why? Which is the stronger base – the acetate ion or the hypochlorite ion? Why? Calculate the Kb values for the acetate ion and the hypochlorite ion. 6

pKa and pKb pKa = -log(Ka) pKb = -log(Kb) pKa + pKb = 14 We will use these a lot more in chapter 16!

Is that salt acidic, basic, or neutral? Separate the salt into its anions and cations Turn the anion into an acid (add a hydrogen ion) Is it a strong acid or a weak acid? Turn the cation into a base (add hydroxide OR remove a hydrogen ion) Is it a strong base or weak base? Cation Anion Result Strong base Strong acid Neutral Weak base Acidic Weak acid Basic ??? (depends on relative strength)

Will each of the following salt solutions be acidic, basic or neutral? NaCl NH4NO3 NH4Br  FeCl3  Na2CO3  KClO4  NaHC2O4

Homework Finish MasteringChem 15.7-15.8 Ch 15 Review Your chapter 15 quiz is tomorrow!!