00:01
Before answering this question, we first need to calculate the kb1 and kb2 values.
00:07
Kb1 can be calculated from pka2.
00:13
Kb1 will be equal to kw divided by ka2.
00:18
Ka2 can be determined from pka2 as 10 to the negative pka2 gives us ka2.
00:25
And then ka2 divided into kw gives us kb1.
00:30
It will be this larger kb value that we use to determine the ph of the solution.
00:38
Kb2 is going to be smaller, and it will be calculated from ka1.
00:44
Ka1 is 10 to the negative pka1.
00:48
We divide that into kw, and we get kb2 of 7 .05 times 10 to the negative 8.
00:56
We'll then use just kb1 at a much larger value to determine the hydroxide concentration.
01:03
Hydroxide concentration will be equal to the square root of the concentration of ethylene diamine, multiplied by the kb1 value.
01:11
We then take the square root and we get 3 .13 times 10 to the negative 3 molar...