which alcohol and carboxylic acid would produce benzyl isobutyrate by Fischer esterification? and which alcohol and carboxylic acid would produce isobutyl benzoate by fischer esterification?

I can't find anything about Fischer esterification specifically. But acids + alcohols produce esters.
Benzoic acid + isobutyl alcohol yields isobutyl bnzoate.
BzCOOH + HOCH2CH(CH3)2 ==> BzCOOCH2CH(CH3)2

isobutyric acid + benzyl alcohol yields benzyl isobutyrate.
(CH3)2CHCOOH + HOCH2Bz==>(CH3)2CHCOOCH2Bz

Again my references don't speak to a Fischer synthesis. I don't know if the above will be helpful or not.
Check my work!

Your understanding of the Fischer esterification is correct. Fischer esterification is a method used to produce esters by reacting carboxylic acids with alcohols in the presence of an acid catalyst. The reactions you provided are indeed examples of Fischer esterification.

To produce benzyl isobutyrate, you would react isobutyric acid (CH3)2CHCOOH with benzyl alcohol (C6H5CH2OH) in the presence of an acid catalyst. The reaction can be represented as follows:

(CH3)2CHCOOH + C6H5CH2OH → (CH3)2CHCOOCH2C6H5 + H2O

To produce isobutyl benzoate, you would react benzoic acid (C6H5COOH) with isobutyl alcohol (CH3)2CHCH2OH in the presence of an acid catalyst. The reaction can be represented as follows:

C6H5COOH + (CH3)2CHCH2OH → C6H5COOCH2CH(CH3)2 + H2O

Both reactions require an acid catalyst, which typically includes strong acids such as sulfuric acid (H2SO4) or hydrochloric acid (HCl). The acid catalyst helps in the formation of the ester by protonating the carbonyl oxygen and promoting the nucleophilic attack by the alcohol.

Remember to always use caution when working with chemicals and consult reliable sources or textbooks to confirm the specific reaction conditions and safety protocols.