We've been working on extraction of known/unknown compound mixtures lately, and we have to give equations for the acid-base reactions that occurs between HCl, NaOh and (a) R-COOH (b) R-NH2, and (c) Neutral compounds (naphthalene and triphenylmethanol)

For (a) carboxylic acids, I wrote:
R-COOH + NaOH --> R-COONa + H20
R-COONa + HCl --> R-COOH + NaCl
(I'm not sure if I am supposed to give the equation of carboxylic acid's subsequent rxn with HCl after NaOH, but I don't know how to do it otherwise)

what about for NH2?
what about neutral compounds?
please explain also. Thanks so much!!!!

5 answers

For (a) carboxylic acids, I wrote:
R-COOH + NaOH --> R-COONa + H20 This is OK. I don't know if its required or not but you can also show the ionization of RCOONa ==> RCOO^- + Na^+.

R-COONa + HCl --> R-COOH + NaCl
(I'm not sure if I am supposed to give the equation of carboxylic acid's subsequent rxn with HCl after NaOH, but I don't know how to do it otherwise)
This is right the way you have it but I would interpret the question as meaning the reaction of RCOOH + HCl for which I would write no reaction.

For the RNH2, this is a base.
RNH2 + HCl ==> RNH3Cl ==> RNH3^+2 + Cl^-
RNH2 + NaOH ==> I would write N. R.; however, some weak bases react with strong bases (such as NaOH) to give NH3 gas but this happens only under very strong conditions; i.e., the NaOH is concentrated and sometimes the mixture is heated. I think, for extraction purposes, the N.R. for NaOH is the proper choice.

For neutral compounds being extracted under the influence of acid or base conditions, I don't believe neutral compounds are affected by HCl or NaOH.

I hope I have interpreted the questins properly.

Thank you so much!! =)
C6H5COOH+HCl
write an equation to explain the interaction of the compound,RNH3Cl with NaOH
equation to show interaction of the compound RNH3Cl with NaOH