Question

What is NOT true for aceto-phenone?
  (A) It gives 2,4-DNP test
  (B) It forms ${C_7}{H_6}{O_2}$ on drastic oxidation with $KMn{O_4},{H^ + }$
  (C) It does not give Tollens or Fehling’s test
  (D) It gives yellow ppt with NaOH, $C{l_2}$

Answer 1

Hint: Aceto-phenone has a ketone functional group and hence there are no hydrogens attached to the carbonyl carbon. Now identify which of the statements is false for ketones.

Complete step by step answer:
-First of all let us see the structure of aceto-phenone. It has a molecular formula of ${C_8}{H_8}O$ and the functional group present in it is a ketone group.
                                                         

-Now we need to check each option to see which of these statements is not true for aceto-phenone.

-For (A) It gives 2,4-DNP test: 2,4 DNP reacts with both aldehydes and ketones. Here aceto-phenone will react with 2,4-Dinitrophenylhydrazine and forms its derivative called the 2,4-Dinitrophenylhydrazone. The reaction can be shown below:

So, we can say that this statement is true.

-For (B) It forms ${C_7}{H_6}{O_2}$ on drastic oxidation with $KMn{O_4},{H^ + }$: When aceto-phenone undergoes drastic oxidation with $KMn{O_4},{H^ + }$ it leads to the breaking or rupture of C-C bond and thus forms benzoic acid which has a molecular formula of ${C_7}{H_6}{O_2}$. This reaction is shown below:

So, this statement is also true.

-For (C) It does not give Tollens or Fehling’s test: They give tests for aldehydes or say compounds which have a hydrogen atom attached to the carbonyl carbon. But here in aceto-phenone there is no such hydrogen atom which is attached to the carbonyl carbon (like in aldehydes) and so they do not give a test for aldehydes and ketones.So, this statement is also true.

-For (D) It gives yellow ppt with NaOH, $C{l_2}$: When aceto-phenone reacts with NaOH and $C{l_2}$, it leads to the formation of chloroform which is colourless. There is no formation of any yellow ppt. This reaction is shown below:

So, this statement is false. So, the correct answer is “Option D”.

Note: Aceto-phenone is the simplest aromatic ketone and has many pharmaceutical applications. It is used in the production of resins and key ingredients in fragrances resembling jasmine, cherry, almond, strawberry, etc.