Oxidation reagent for alcohol and aldehyde groups

Steps:

• Compound X has a primary alcohol and an aldehyde, both oxidizable.
• Acidified K2Cr2O7 oxidizes primary alcohols to carboxylic acids via aldehydes.
• It also oxidizes aldehydes directly to carboxylic acids.
• Other reagents target only one group, not both.

Why A is correct:

• Acidified potassium dichromate(VI), [O], oxidizes both -CH2OH to -COOH and -CHO to -COOH per standard organic oxidation rules.

Why the others are wrong:

• B. 2,4-DNP forms hydrazones only with carbonyls, ignoring alcohols.
• C. Hydrazine forms hydrazones with carbonyls but does not react with alcohols.
• D. NaBH4 reduces carbonyls to alcohols but leaves existing alcohols unchanged.

Final answer: A