00:01
Let's calculate the ph of a 0 .2 molar solution of a chlorobenzoic acid.
00:05
We'll first start with the conjugate sodium chlorobenzate, c -l -o -2.
00:19
This will break apart to n -a -plus and c -7h4 -c -l -o2 minus, which is going to act as a weak base.
00:32
And we're told that this is 0 .20 molar, therefore this is also 0 .2 .2.
00:37
To zero molar.
00:38
And the solution also has a ph that's equal to 8 .65.
00:46
Therefore, the poh would be equal to 14 minus 8 .65, which is equal to 5 .35.
00:55
And based on that, the hydroxide and malaria is 10 to the minus 5 .35, which would be equal to 4 .5 times 10 to the negative 6 molar.
01:14
Using this information, let's solve for the kb for c7h4clo2 minus.
01:25
Their equilibrium would be h, c7h4clo2, and ohm minus.
01:37
Initial change equilibrium.
01:40
Initial is 0 .20.
01:42
This here, oh, h minus, is 4 .5 times 10 to the negative 6, 0 and 0, plus, 4 .5 times 10 to the negative 6.
01:51
Let's complete our ice table and subtracting here we'll just yield 0 .20.
02:03
The kb, do our kb expression...