B
bdrunner79
Guest
Sure no problem at all. I hope it made sense.
To extrapolate your discussion to an absolute measurement, if you remeraber from chemistry the measure of dissociation for aciRAB is called the Ka. The negative logarithm is the pKa. The lower the pKa, the stronger the acid. For instance, HCl is -4.
I looked up some data and found that acetic acid's pKa is 4.75, which is pretty weak. Lemon juice could have citric acid, which has 3 hydrogens to lose vs. 1 hydrogen in acetic acid. So it has 3 chances to lose a hydrogen, and consequently has 3 pKa's, depending on what hydrogen you're talking. The first hydrogen to go has a pKa of 3.13, second is 4.76, and the third is 6.40. Phosphoric acid also has 3 pKa's, of 2.15, 7.20 and 12.35.
Why is this important you're probably asking, haha. Well, in this narrow case, if you are trying to buffer the HCl, with a pKa of -4, you'd want a weak acid with its first pKa as far away as possible. So acetic acid has 4.75, which is better than 3.13 and 2.15, which fully explains why vinegar works better for you vs. lemon juice. Lemon juice will work, not as well, and certainly tastes better though.
Here's another thought though. Just because acetic acid is labeled an acid and usually is an acid, we simply label things based on what they behave as in WATER. If you would mix acetic acid with HCl, like you do in your stomach, it is actually acting as a BASE, not an acid. It depenRAB on what else is present. Water is a weaker acid than acetic acid, so acetic acid "gets" to act as an acid. However, when mixed with HCl, HCl is the stronger acid, so acetic acid is the base.
There's a lot more to it of course, but I think I've given everyone (and myself) a headache at this point in the evening.
And yes, any vinegar works just fine.
To extrapolate your discussion to an absolute measurement, if you remeraber from chemistry the measure of dissociation for aciRAB is called the Ka. The negative logarithm is the pKa. The lower the pKa, the stronger the acid. For instance, HCl is -4.
I looked up some data and found that acetic acid's pKa is 4.75, which is pretty weak. Lemon juice could have citric acid, which has 3 hydrogens to lose vs. 1 hydrogen in acetic acid. So it has 3 chances to lose a hydrogen, and consequently has 3 pKa's, depending on what hydrogen you're talking. The first hydrogen to go has a pKa of 3.13, second is 4.76, and the third is 6.40. Phosphoric acid also has 3 pKa's, of 2.15, 7.20 and 12.35.
Why is this important you're probably asking, haha. Well, in this narrow case, if you are trying to buffer the HCl, with a pKa of -4, you'd want a weak acid with its first pKa as far away as possible. So acetic acid has 4.75, which is better than 3.13 and 2.15, which fully explains why vinegar works better for you vs. lemon juice. Lemon juice will work, not as well, and certainly tastes better though.
Here's another thought though. Just because acetic acid is labeled an acid and usually is an acid, we simply label things based on what they behave as in WATER. If you would mix acetic acid with HCl, like you do in your stomach, it is actually acting as a BASE, not an acid. It depenRAB on what else is present. Water is a weaker acid than acetic acid, so acetic acid "gets" to act as an acid. However, when mixed with HCl, HCl is the stronger acid, so acetic acid is the base.
There's a lot more to it of course, but I think I've given everyone (and myself) a headache at this point in the evening.
And yes, any vinegar works just fine.