NaBH4 is a mild __ agent that converts carbonyl to __.

NaBH4, or sodium borohydride, is known as a mild reducing agent. This means it is capable of donating electrons to other species, facilitating the reduction of compounds. When NaBH4 interacts with a carbonyl group, such as those found in aldehydes and ketones, it adds hydrogen to the carbonyl carbon, effectively converting the carbonyl functional group into an alcohol.

The reaction occurs because the hydride ion (H-) from NaBH4 attacks the electrophilic carbon of the carbonyl, leading to the formation of an alkoxide intermediate. This intermediate can then be protonated, usually by water or another protic solvent, to produce the final alcohol product.

Thus, the role of NaBH4 as a reducing agent is key in this transformation, and the product of the reaction is an alcohol, confirming that NaBH4 reduces carbonyl compounds to alcohols. This understanding is fundamental in organic chemistry and biochemical pathways, highlighting the importance of reduction reactions in the synthesis of various organic compounds.