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    Q: Which reactions must be warmed to form a solid product?
    1) CH3CH2CHO + 2,4-dinitrophenylhydrazine reagent
    2) CH3CH2CHO + Fehling’s reagent
    3) CH3CH2CHO + Tollens’ reagent

    The answer is only 2) and 3).
    But shouldn't 1) give an orange ppt as well since 2,4-DNPH reacts with aldehydes?
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    (Original post by sourmango1)
    Q: Which reactions must be warmed to form a solid product?
    1) CH3CH2CHO + 2,4-dinitrophenylhydrazine reagent
    2) CH3CH2CHO + Fehling’s reagent
    3) CH3CH2CHO + Tollens’ reagent

    The answer is only 2) and 3).
    But shouldn't 1) give an orange ppt as well since 2,4-DNPH reacts with aldehydes?
    It does give a ppt. Perhaps the question is more about whether you need to warm it. I don't believe that is necessary with 2,4 DNP but it is necessary in the Tollen's and Fehling's tests
 
 
 
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