Exam questions in my email...

A couple questions have trickled in to my email box...
--Question 1------------
Quick question, what does it mean to be diprotic or monoprotic? And how do you know if something is diprotic monoprotic?
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This refers to how many acidic protons (H+) there are on an acid, how many protons can be donated. Something like HCl(aq) only has 1 H+ to donate so it's monoprotic. Phosphoric acid has 3 acidic H+ so it's triprotic. Usually it's just a matter of "count the H's" in the formula, but for organic acids (and some others...) there are H's that are not acidic. Think of the acetic acid you used in lab... CH3COOH(aq)... the 3 H's that are connected to carbon are not acidic, only the H attached to oxygen is acidic, so this is a monoprotic acid.
I will often use shorthand terminology and refer to bases as being "monoprotic" to mean that the base can accept only 1 proton or "diprotic" if the base can accept 2 protons.


--Question 2------------
On one of the practice exams there is a question that asks for a detailed titration curve. What exactly would you be looking for in something like that as far as details to include?
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You caught me... I usually don't include those drawings in the keys because I type the keys and those titration curves are a little hard to draw electronically... I've drawn a couple and they look horrible. When drawing a titration curve like this, you should label any equivalence points, indicate the species present in solution, label any pH's you can reasonably estimate (or might know...), maybe something like this:

You don't have to label all of those pH values, but again, if you know the pH values for some of those points, you might as well use them to draw a titration curve that's a little more quantitatively accurate.

Other questions, let me know.