00:01
When we add the hydroxide, sodium hydroxide, to the solution, the hydroxide of sodium hydroxide is going to react with the acid and make its conjugate base in water.
00:13
As long as we don't add more hydroxide than we have at the acid, we'll still have some acid, but we would have produced its conjugate base.
00:22
Thus, we'll have a buffer solution containing both the weak acid and its conjugate base.
00:27
Ph can be calculated for a buffer solution using the henderson -hasselbalch equation, where ph equals pka plus the log of the moles of the base formed, divided by the moles of the acid still left in solution.
00:44
A lot of times people will do a ratio of molarities, but a ratio of moles works equally, and sometimes it's easier as in this case.
00:53
So ph will be equal to pka.
00:57
Pka is going to be the negative log of the ka value for the acid.
01:02
They gave that to us as 9 .8 times 10 to the negative 4...