Acidic Protons

[jdpaul14]

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Hey guys,

For acetic acid, is the acidic proton the proton connected to the Oxygen or the proton connected to the Carbon?

....asking because I found out that in Methylamine, the acidic proton is connected to the Nitrogen.

Also, whats the acidic proton in Methanol and Propyne?


Thanks a lot,

 

[pbure9]

On acetic acid, the H connected to the OH is definitely the one more acidic.

On methylamine, it ctan't be anywhere but on the Nirogen.

As for methanol, the acidic proton is on the O and in propyne its on the lone H off the triple bonded carbon. It can be taken off with a strong base like NH2-.

These things you should know for the orgo section very well I'd say

 

[nze82]

The acidic proton is always the one connected to O. Why?
Oxygen is very electronegative, pulling hard on the electron cloud of H. Under such circumstances H will be more willing to give of it's electrons and get released as H+, and as we know compounds that easily release H+ are acidic.
The H connected to C cannot be acidic based on the same logic. C is not nearly as electronegative as O. Therefore, it doesn't pull as strongly on the electron cloud of H. Under such circumstances, the hydrogen is not willing to give up its electrons and therefore, it doesn't get released as H+. Thus, it can't be acidic!