Question

Primary alcohols oxidize to form _____.

Answer 1

Answer: Aldehyde ;)

Explanation: Reacting with strong oxidizing agent primary alcohol will produce carboxylic acids via aldehydes and when treated with mild oxidizing agent primary alcohol will produce aldehyde.

Answer 2

Answer:
            Primary alcohols oxidize to form Carboxylic Acids.

Explanation:
                   Primary Alcohols when treated with Oxidizing agents like K₂Cr₂O₇ and CrO₃ produces carboxylic Acids as a final product. This oxidation to Carboxylic Acid first passes through Aldehydes and then is oxidized to carboxylic Acid. 
                   As K₂Cr₂O₇ and CrO₃ are strong oxidizing agents, if a mild oxidizing agent like Pyridinium Chlorochromate (PCC) is used then primary Alcohol will convert into Aldehyde. 
                   So, on reacting with strong oxidizing agent primary alcohol will produce carboxylic acids via aldehydes and when treated with mild oxidizing agent primary alcohol will produce aldehyde.