Ochem acidities

[Deepa100]

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Hi,
Does any one find it useful to memorize certain Pka values for alchols, water, caboxylic acids, amines etc.? I did for my Ochem class but I am not sure if I have to for the MCAT. I do have a general order that I will memorize but do I need the actual Pka values? Will it help?

 

[sleepy425]

no, please don't.

 

[Kaustikos]

Hi,
Does any one find it useful to memorize certain Pka values for alchols, water, caboxylic acids, amines etc.? I did for my Ochem class but I am not sure if I have to for the MCAT. I do have a general order that I will memorize but do I need the actual Pka values? Will it help?

No way in hell. They'll tell you.

 

[Franksta1118]

I read somewhere, either Princeton or tbr, that a good trend to remember was CPAC, Carboxylic Acid > Phenol > Alcohol > Carbonyl alpha hydrogen, just as a general trend going from most acidic to least acidic, I don't have the associated pKa values but 5, 10, 15, 20 seems to ring a bell...

 

[RSAgator]

I think it's MUCH more important to know relative acidities and what kinds of things contribute to acidity. For instance the hydrogen at the alpha carbon is acidic because of the resonance in the carbonyl. The MCAT is much more focused on qualitative knowledge (carboxylic acid is more acidic than aldehyde) than on quantitative (carboxylic acid has a pKa of x whereas aldehyde has a pKa of y).

 

[Vihsadas]

I think it's MUCH more important to know relative acidities and what kinds of things contribute to acidity. For instance the hydrogen at the alpha carbon is acidic because of the resonance in the carbonyl. The MCAT is much more focused on qualitative knowledge (carboxylic acid is more acidic than aldehyde) than on quantitative (carboxylic acid has a pKa of x whereas aldehyde has a pKa of y).

Yes exactly. Comparative trends are very important, but specifics are not.