Question

1. Write the dissociation reaction and the corresponding K, equilibrium expression for each of the following )HCN bHOC.H 2. You may need Table 14.2 to answer the following questions a) Which is the stronger base, CT or HO b) Which is the stronger base, HiO or NO? c) which is the stronger base, Cr or OCH,7 3. Calculate the [H"1 of each of the following solutions at 25 C. Identity each solution as neutral, acidic, or basic. a) [OH] . 3.6 x 10""M b) [OH] 7.3 x 10 M 4. Values of K, as a function of temperature are as follows: Temperature(C)K 25 35 40. 1.14 x 10 1.00 x 10 2.09x 10 2.92 x 10 5.47 x 10 a. Is the autoionization of water exothermic or endothermic? b. Calculate [H'] and [OH] in a neutral solution at 50.°C 5. Calculate the [OH] of each of the following solutions at 25°C. Identify each solution as neutral, acidic, or basic. a) [H'] 1.Ox 10M 6. An antacid purchased at a local drug store has a pOH of 2.3. Calculate the pH, [H'1, and IOH] of this b) [H' 8.3x 10s M solution. Is the antacid acidic or basic? 7. Calculate the pH of each of the following solutions containing a strong acid in water a) 2.0x 10 M HNO b) 4.0 M HNO 8. What are the major species present in 0.250 M solutions of each of the following acids? Calculate the pH of each of these solutions a) HOCHs b) HCN 1.0x 10), 0.20 MHB (K,-1.0x10), and 0.10 M 9. A solution contains a mixture of acids: 0.50 M HA K HC (K, 1.0x 10). Calculate the [H'] in this solution.

Answer 1

Ans 1

Part a

The dissociation reaction of HCN

HCN(aq) + H2O(l)⇌H3O+ + CN-(aq)

Equilibrium constant expression of the reaction

Ka=[H3O+][CN-]/[HCN]

Part b

The dissociation reaction of C6H5OH

C6H5OH + H2O ==> H3O+ + C6H5O-

Equilibrium constant expression of the reaction

Ka = [H3O+] [C6H5O-] /[C6H5OH]

Part C

The dissociation reaction of C6H5NH3+

C6H5NH3+ + H2O <----> H3O+ + C6H5NH2

Equilibrium constant expression of the reaction

Ka = [H3O+] [C6H5NH2] /[C6H5NH3+]