Given that the ka for hocl is 3.5 × 10–8, calculate the k value for the reaction of hocl with oh–.
a. 3.5 × 10–22
b. 3.5 × 10–8
c. 2.9 × 10–7
d. 3.5 × 106
e. none of these

D

3.5 * 10^6

Explanation:

In this question, we are asked to calculate the the k-value for the reaction of HOCl with OH- given Ka value for HOCl

Firstly, we write the dissociation equation for HOCl

This is as follows;

HOCl ——> H+ + OCl-

Now, we write an expression for Ka

Ka = [H+][OCl-]/HOCl = 3.5 * 10^-8

Now, we write an equation for the reaction of HOCl and OH- ;

HOCl + OH- —-> OCl- + H2O(l)

The K value expression for this can be written as;

K = [OCl-]/[HOCl][OH-]

= [H+][OCl-]/[HOCl] * [1/[H+][OH-]

= ka * 1/Kw = 3.5 * 10^-8 /(1 * 10^-14) = 3.5 * 10^6

i just learnt this recently but i need to look through my notes again