Class 12th

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

Correct options are a and b.

Purines are made up of a six-membered nitrogen-containing ring joined with a five-membered nitrogen-containing ring.

Purine bases are guanine and adenine, while pyrimidine bases are thymine and uracil.

 

Hence (a) and (b) are correct choices for this question.

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 Answer Type Questions as classified in NCERT Exemplar

Correct options are b and d.

Fibrous protein is generated when the polypeptide chain runs parallel and is held together by hydrogen and disulphide bonds.

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 Answer Type Questions as classified in NCERT Exemplar

Correct options are a and c.

The cyclic structure of ribose and fructose is five-membered (furanose structures). Like compound furans, they have a five-membered ring.

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

Correct options are a, b and c.

Lysine is an amino acid with the structural formula of (a).

(b) Because the number of groups (two) is more than the number of -COOH groups (one), it is a basic amino acid (one).

Because it is created in human bodies, it is a non-essential amino acid.

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 Answer Type Questions as classified in NCERT Exemplar

Correct options are b and d.

Acidic amino acids are divided into two groups, one -COOH group against the other - NH₂ group. As a result, the acidic amino acids (b) and (d) are the only ones among the supplied structures.

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.