The reagent (s) that can be used to distinguish between methanol and ethanol are (a) Anhydrous \(\mathrm{ZnCl}_{2} / \mathrm{con} . \mathrm{HCl}\) (b) salicylic acid/con. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (c) Acetic anhydride (d) \(\mathrm{I}_{2} / \mathrm{NaOH}\)

For each given reagent, consider its chemical properties and how methanol and ethanol might react with them. (a) Anhydrous \(\mathrm{ZnCl}_{2} / \mathrm{con} . \mathrm{HCl}\) - Lucas Reagent: This reagent is used to distinguish primary, secondary, and tertiary alcohols. However, both methanol and ethanol are primary alcohols, so this reagent cannot distinguish between them. (b) Salicylic acid/con. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) - Esterification: This reaction forms an ester from an alcohol and a carboxylic acid in the presence of a strong acid. The resulting esters will have different structures and smells, allowing us to distinguish between methanol and ethanol. (c) Acetic anhydride - Esterification: Similar to option (b), this reaction also forms an ester from an alcohol. The resulting esters will have different structures and smells, allowing us to distinguish between methanol and ethanol. (d) \(\mathrm{I}_{2} / \mathrm{NaOH}\) - Iodoform reaction: This reaction forms iodoform (CHI3) when an alcohol has a methyl group (CH3) attached to the hydroxyl (OH) carbon. Methanol reacts with this reagent, but ethanol does not, as it lacks the necessary methyl group.

Based on the analysis in Step 1, we can conclude that the following reagents can be used to distinguish between methanol and ethanol: (b) Salicylic acid/con. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (esterification) (c) Acetic anhydride (esterification) (d) \(\mathrm{I}_{2} / \mathrm{NaOH}\) (iodoform reaction) Therefore, the correct answer is reagents (b), (c), and (d).