Class 12th

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: ( C)

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (D)

Gabriel synthesis reaction:  

Gabriel's 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 method cannot produce aromatic primary amines because aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (C) 

Potassium cyanide, as cyanide on reduction with sodium metal in alcohol, produces amine with increased carbon atoms. 

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (B)

Lithium aluminum hydride in ether is a strong reducing agent that donates its H? hydride ion to any C=O containing a functional group. In addition to LiAlH₄ to aryl nitro compounds, no reaction will be observed, the desired products of amines will not be produced, rather it will form diazobenzene products.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: (C) 

S_N¹ reaction: A nucleophilic reaction that occurs in two steps, first is the bond-breaking step and the second is the production of the carbocation. The stability of carbocation formed in the second step determines the rate of reactivity of reactant toward S_N¹ reaction.  Here, C₆H₅CH₂Br,  

In the process of ionization, removal of bromine, a stable Benzyl carbocation is produced. Therefore, it is best suited for reaction through the S_N¹ mechanism. 

This is a multiple choice answer as classified in NCERT Exemplar

(b) Equanil is a tranquilizer used in controlling depression and hypertension.

This is a Multiple Answer Type Questions as classified in NCERT Exemplar

The Correct option is b.

Nucleic acids are nucleotide polymers linked together by phosphodiester linkage. DNA and RNA are two examples. Nucleotides are formed by linking of nucleosides with three phosphate groups consuming a significant amount of energy making it an endothermic reaction.

This is a Multiple Answer Type Questions as classified in NCERT Exemplar

(a) 5′ and 3′ linkages are present between pentose sugars of nucleotides.

Phosphodiester links the two nucleotides together to form a dinucleotide.

Between the pentose sugars of nucleotides, there are 5′ and 3′ connections. In the process of adding phosphate to a dinucleotide, a significant quantity of energy is consumed.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans:  (A) 

The NH₂ group is directly attached to the benzene ring in aniline and other aryl amines. As a result, the unshared electron pair on the nitrogen atom is conjugated with the benzene ring, making it less available for protonation.