Final answer:
Sodium borohydride (NaBH4) cannot reduce carboxylic acids or their derivatives like esters to alcohols, whereas lithium aluminum hydride (LiAlH4) is capable of such reductions.
Step-by-step explanation:
The sodium borohydride (NaBH4) is a reducing agent commonly used in organic chemistry for the reduction of aldehydes and ketones to their corresponding alcohols. However, it is not strong enough to reduce carboxylic acids or their derivatives such as esters. This is because the hydride ions from NaBH4 are not reactive enough to reduce the more oxidized carbon atom in the carboxylic acid or ester functional groups.
In comparison, lithium aluminum hydride (LiAlH4) is a much more potent reducing agent. It is capable of reducing not only aldehydes and ketones but also carboxylic acids, acid halides, esters, and amides to their corresponding alcohols. This makes LiAlH4 the reagent of choice for reducing these more stubborn functional groups.