Question

Benzoic acid is stronger than cyclohexane carboxylic acid

Answer 1

pKa is a measure of acid strength. The lower the pKa value, the stronger the acid. (It works similar to the pH scale, the lower the number the more acidic.) The pKa value of cyclohexane carboxylic acid is 4.90 and the pKa value of benzoic acid is 4.20. Neither of these is particularly strong acids, so I don’t think you can actually name a strong acid between them. For example, acetic acid, which is considered to be a weak acid has a pKa value of 4.76) However, if you get a table of pKa values and find an acid that is between those values and close to 4.20 that will be the best sort of answer you can find. Either google for a table of pKa values or you can use this one.