74. Calculate the ionization constant (hydrolysis constant) for each of the following acids or bases:

Question

74. Calculate the ionization constant (hydrolysis constant) for each of the following acids or bases: Use Ka for HF = 7.2 x 10-4 and Kb for NH3 = 1.8 x 10 -5
a) F - d) NH4+

Answer 1

To answer this question first write down the equilibrium reactions in parts a and b.

 

In part a)

 

F^- <=> HF + OH^-

 

In this case you can see that F^- is a base so you need to find K_b using the formula K_a*K_b = K_w where K_w = 1.0 x10^-14. All you need to do know is to solve for K_b.

 

In part d)

 

NH₄⁺ <=> NH₃ + H⁺

 

In this case NH₄⁺ is an acid so you need to find K_a using the same formula as in part a.

 

Try to solve these two on your own. If you're still having trouble let me know.