Question

the ______ of aldehydes or primary alcohols forms carboxylic acids.
reduction
hydrogenation
oxidation
alkylation
sulfonation

Explanation:

Oxidation is a chemical reaction that involves the loss of electrons or an increase in oxidation state. Aldehydes (\(R - CHO\)) and primary alcohols (\(R - CH_2OH\)) can undergo oxidation reactions. For example, the oxidation of a primary alcohol (\(R - CH_2OH\)) first forms an aldehyde (\(R - CHO\)) (by losing two hydrogen atoms, a dehydrogenation - like step in the oxidation process) and then further oxidation of the aldehyde (by adding an oxygen atom in a way that the \( - CHO\) group is converted to \( - COOH\)) forms a carboxylic acid (\(R - COOH\)).

Reduction is the opposite of oxidation (gain of electrons or decrease in oxidation state), hydrogenation is a type of reduction reaction (addition of hydrogen). Alkylation is the addition of an alkyl group (\(R-\)), and sulfonation is the addition of a sulfonic acid group (\( - SO_3H\)), neither of which convert aldehydes or primary alcohols to carboxylic acids.

Answer:

oxidation