Chemistry NCERT Exemplar Solutions Class 12th Chapter Thirteen

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: a and b  

In addition to the nitro derivatives, direct nitration of aniline produces tarry oxidation products. Furthermore, aniline is protonated in the strongly acidic medium to form the anilinium ion, which is meta directing. As a result, in addition to the ortho and para derivatives, a significant amount of meta derivative is formed.

However, by protecting the? NH₂ group with an acetylation reaction with acetic anhydride, the nitration reaction can be controlled and the p-nitro derivative obtained as the main product.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option a and c

(a) Primary alkyl halides react with ammonia to give primary amines. Correct reaction.

(B) Elimination process doesn't occur with aq. KOH, hydrolysis process takes place. (B) is incorrect. 

(c) Dehydrohalogenation I.e. elimination of HCl occurs which produces alkene as the product takes place with alc. KOH . (c) is correct.

(d) In this reaction, aliphatic primary amines, on treatment with nitrous acid, produce primary alcohol as a product.

Therefore (d) is incorrect. 

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (a and b) 

Gabriel synthesis is a method for producing primary amines. When phthalimide is treated with ethanolic potassium hydroxide, it forms a potassium salt of phthalimide, which when heated with an alkyl halide and then alkaline hydrolyzed yields the corresponding primary amine.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: A, B & C  

As the NH₂ group is Ortho para directing group, so Br⁺ attacks only at the o and p positions thus the products formed corresponds to the option A, B and C.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: Option a and b

NHCOCH₃ is an ortho- para directing group so ortho-para products are formed. 

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option (B and C) 

Certain mild reducing agents like hypophosphorous acid (phosphinic acid) or ethanol reduce diazonium salts to arenes and themselves get oxidised to phosphorous acid and ethanol, respectively.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (A and B)

When aliphatic and aromatic primary amines are heated with chloroform and ethanolic potassium hydroxide, they form isocyanides or carbylamines, which have a foul odor. This reaction does not occur in secondary or tertiary amines.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (A, B & C) 

Nitro compounds are reduced to amines by passing hydrogen gas through an acidic medium containing finely divided nickel, palladium, or platinum, as well as by reduction with metals in an acidic medium.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (C and D) 

Chlorobenzene and bromobenzene are prepared by the sandmeyer's reaction. 

While fluorobenzene and iodobenzene are prepared by simple heating of diazonium salt with aqueous KI Solution.