posted by Nancy on .
what are the other chemistry forms present in the dichloromethane solution besides the normal neutral forms for benzoic acid and quinine?
(benzoic acid,pKa 4.2; quinnie, pKa 8.5)
You apparently refer to a lab or a question you are to answer BUT there isn't enough information for us to know what you are doing. We don't have access to your syllabus, you texts, your notes, etc. Please provide the complete question.
i have to separate benzoic acid from a mixture with quinine.
so benzoic acid and quinine are qissolved in Ch2Cl2. i think the question is asking wether there's any other chemical forms in the mixture apart from the neutral forms for benzoic acid and quinine, but i am really lost.
Since benzoic acid is an acid and quinine is a base, there is the possibility of them reacting to produce a salt. I don't have a set of tables, perhaps you do, that will give you the conjugate acid strengths.
Bacid + quin ==> Bconj base + qconj acid
acid + base ==> conj base + conj acid
Since pKa is given for the acid and the base, see if you can find pKa for the conjugate base and conjugate acid of the two. If so, the rule is that the reaction will take place if you can go from strong to weak; i.e., strong acid to weaker acid or strong base to weaker base.
If the pKa of benzoic acid is given as 4.2 and of quinine as 8.5 what does this mean for the reactions?