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Why is Brady's test negative(DNPH gives no PPT)for carboxylic acids? Watch

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    Although an orange ppt is formed with aldehydes and ketones?
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    Hi,

    this thread explains it quite well. Look at the top answer.

    http://chemistry.stackexchange.com/q...rboxylic-acids
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    (Original post by sophiebookley)
    Hi,

    this thread explains it quite well. Look at the top answer.

    http://chemistry.stackexchange.com/q...rboxylic-acids
    thanks! i understand now but without the details. Do we need to know about resonant structures for alevels ?
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    I'm not sure about all exam boards, but I do OCR A and we don't. In fact, I don't think we even have to know why 2,4 DNPH produces a precipitate with aldehydes/ketones versus carboxylic acids. We just have to know a basic version of the test for a C=O in aldehydes and ketones and a bit about 2,4 DNPH itself (it's full systematic name, precipitate colour etc). But, like I said, I'm not sure about other exam boards. Maybe check the specification or ask a teacher?
 
 
 
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