2. Why is it easier to remove excess acetic acid from the products than excess isopentyl alcohol?

Answer 1

It depends on what the 'products' are.

Excess acetic acid (ethanoic acid) is usally removed from a material by shaking the mixture (that has been taken up in an organic solvent) with an aqueous carbonate solution or a NaOH solution.
Depending on the scale, how much acetic acid and what the 'products' are, there other 'tricks'. If there is only a small amount of acetic acid then 'drying' an organic solvent solution of the mixture over anhydrous sodium carbonate powder will remove the acid. You can also achieve the same result by adding basic alumina powder, that is used for chromatography.

An alternative method using the alumina chromatography powder is to pass the mixture in an organic solvent down a short chromagraphy column of alumina powder.

The isopentyl alcohol (bp 133C) can be hard to remove, but it depends on what the 'products' are.