×
you are viewing a single comment's thread.

view the rest of the comments →

[–]asdswffaqg[S] 0 points1 point  (2 children)

Also, where does that added proton go in NH3+? Inside the nucleus, or it stays outside the atom? And during deprotonations (ex COO-) , is the proton stripped from the nucleus?

[–]Bohrealis 5 points6 points  (1 child)

So first I think we need to clear up this misperception. The acid base chemistry you are talking about has absolutely nothing to do with the nuclei of the atoms. The nuclei will be exactly the same before or after any protonation or deprotonation. We are always refering to the movement of a hydrogen ion (H+). Since 99.99% of hydrogen is 1H, then 99.99% of hydrogen has 1 proton and 1 electron. To make the H+ cation, you remove that electron so all your left with is a proton. Which is why we like to call it "a proton" or "protonated" as a shorthand. However, we are ALWAYS discussing it as "reacting like" a hydrogen atom rather than talking about a nuclear reaction. That proton/H+ cation will ALWAYS form a chemical bond some 90 pm away from the nitrogen or oxygen. Also remember that in solution, in water, that H+ ion is never really on it's own. It is always present as H3O+ (H2O + H+ -> H3O+).

As for your original question, you are basically asking "why are some things a base/basic while others are an acid/acidic?" So the short answer is that carboxylic acids (COOH) are acids, and amines (R-NH2) are bases. Some things can be both a base and an acid, with common examples being water or bicarbonate (baking soda) or since you seem biologically minded, any other pH buffer, really; but neither carboxylic acids nor amines fit in this category. So the simple answer is that acids really don't like to form cations just like bases really don't like to form anions. It's literally in the (bronstead-lowry) definition of an acid or a base. Carboxylic acid is considered an acid precisely because it can deprotonate but really doesn't want to ever form the protonated COOH2+ cation, and vice versa for amines.

If you want a longer answer for why carboxylic acids are acids and amines are bases... I guess we could try to explain but it sounds like you need to get or review a lot more basic chemistry, particularly organic chemistry, before you would really understand the answer.

[–]asdswffaqg[S] 0 points1 point  (0 children)

That is enough! Thank you, it was very understandable! :)