Identify an Unknown Carbonyl Compound

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Identify an unknown carbonyl compound
© KCl
           To classify a carbonyl compound by a simple test and to identify it by the precipitation of a derivative. Principle
           In this experiment, the unknown compound is either an aldehyde or a ketone from Table 90. In the first part, on undergoing Tollen's & Fehling's tests, ketone will have no reaction. In the second part, by preparing a derivative of the compound with 2,4-dinitrophenylhydrazine, the sharp melting point can be used to identify the unknown carbonyl compound.            Carbonyl compound can form a precipitate with 2,4-dinitrophenylhydrazine with high melting point:                       [pic]

© KCl
             My sample is:          ethanal          

|1.> It forms a silver mirror with Tollen's reagent: | |              CH3CHO   +   2Ag(NH3)2OH   →   RCOO-NH4+   +   2Ag(s)↓   +   H2O   +   3NH3 | | | |2.> It turns deep blue Fehling's solution to green: | |              CH3CHO   +   2Cu2+   +   5OH-   ─△→   RCOO-   +   CuO(s)↓   +   3H2O | | | |3.> When reacted with 2,4-DNP, it forms an orange precipitate, with melting point 148℃:...
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