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)
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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?
To determine the other forms present in a dichloromethane solution of benzoic acid and quinine, we need to consider their acid-base properties and the pKa values provided.
Benzoic acid (pKa 4.2) and quinine (pKa 8.5) can exist in three different forms: the neutral form, the protonated form (acidic), and the deprotonated form (basic).
1. Neutral form: This is the form of the compound that does not have an excess of either protons (H+) or hydroxide ions (OH-). In the case of benzoic acid, the neutral form is the predominant species at lower pH values (acidic conditions). Similarly, for quinine, the neutral form is the main species at higher pH values (basic conditions).
2. Protonated form: This form occurs when the compound accepts a proton (H+), becoming positively charged. In the case of benzoic acid, protonation occurs at the carboxylic acid group (COOH), forming the benzoate ion (C6H5COOH+). For quinine, protonation typically occurs at the nitrogen atom, resulting in a positively charged quinine ion (C20H24N2+).
3. Deprotonated form: This form arises when the compound donates a proton (H+), becoming negatively charged. In the case of benzoic acid, deprotonation occurs when the carboxylic acid group loses a hydrogen atom, forming the benzoate ion (C6H5COO-). For quinine, deprotonation typically occurs at the nitrogen atom, resulting in a negatively charged quinine ion (C20H23N).
So, in a dichloromethane solution of benzoic acid and quinine, we can expect to have the neutral forms, the protonated forms, and the deprotonated forms of both compounds, depending on the pH of the solution. The relative proportions of these forms will vary based on the specific pKa values and the pH of the solution.