Question

Consider the following reaction:

The product ‘P’ gives a positive ceric ammonium nitrate test. This is because of the presence of which of these –$\mathrm{OH}$ group(s) ?

• A. (b) only
• B. (b) and (d)
• C. (c) and (d)
• D. (d) only

Answer 1

The correct option is A

(b) only

Explanation of incorrect option:

(A) The ceric ammonium nitrate test of ‘P’ is explained below:

1. Since chromic anhydride(${\mathrm{CrO}}_3$) is a strong oxidizing agent it reduces primary, secondary and allylic alcohol but is unable to oxidize tertiary alcohol.
2. All the $-\mathrm{OH}$ group in the above compound will oxidize except the ‘b’ tertiary alcohol.
3. Ceric ammonium nitrate test is used for the identification of aliphatic alcohol.
4. Since ‘b’ $-\mathrm{OH}$ group unaffected by ${\mathrm{CrO}}_3$ test so Ceric ammonium nitrate reacted with the ‘b’ $-\mathrm{OH}$ group to give red colour.

Therefore, the above points and diagram explain the presence of ‘b’ group to give positive ceric ammonium test.

Explanation of incorrect option:

(B) The ‘d’ group attacked by ${\mathrm{CrO}}_3$ and can't give a positive ceric ammonium test. Therefore option B is incorrect.

(C) The 'c and ‘d’ groups attacked by ${\mathrm{CrO}}_3$ and can't give positive ceric ammonium test. Therefore option C is incorrect.

(D) The ‘d’ group attacked by ${\mathrm{CrO}}_3$ and can't give a positive ceric ammonium test. Therefore option D is incorrect.

Therefore, option A is correct.