00:01
To calculate the ratio of the ionized form to the unionized form, or actually the ionized form to the unionized, then that's going to be the deprotonated form divided by the protonated form, which is what we find in the henderson -hasselbalch equation.
00:20
So we'll use that, ph is equal to pka plus the log of the deprotonated form, the ionized form to the unionized form.
00:41
The ph in which the acid is going to be found is the ph of the stomach, 1 .2.
00:48
We'll set that equal to its pka of 3 .0, and then add to that the log of the ratio we're interested in.
01:04
If we then subtract 3 from both sides, we get negative 1 .8 is equal to the log of the ratio.
01:14
And then if we take the antilog base 10 of both sides, that's 10 to the, 10 to the negative 1 .8, gives us 0 .1, actually 0 .0158 as the ratio we're interested in.
01:40
Then it wants to know the percent of the unionized form of the drug in the stomach.
01:46
So the unionized form is the protonated form.
01:51
It's ionized when you take off a hydrogen, it becomes an ion...