Class 12th

This is a multiple choice answer as classified in NCERT Exemplar

(a, b)

(a) Sulphapyridine is a sulphonamide antibacterial drug.

(b) Prontosil is also called sulphamidochrysoidine.

(c) Salvarsan is arsenic based antibacterial drug.

(d) Nardil is an antidepressant drug.

This is a multiple choice answer as classified in NCERT Exemplar

(a, b) Barbiturates are tranquilizers which are used as hypnotics or sleep inducing agents.

This is a multiple choice answer as classified in NCERT Exemplar

(b, c)

(a) CHCl₃  (chloroform) was used as an anaesthesia in surgery but now it is used in the production of the Freon refrigerant R-22.

(b) Iodoform (CFH₃) produces iodine on coming in contact with skin, so it is used as an antiseptic for wounds.

(c) Boric acid (IT₃BO₃) in dilute aqueous solution is a weak antiseptic for eyes. Thus, chemical messenger gives message to the all without entering the cell.

(d) Chlorine in the concentration of 0.2 of 0.4 ppm in aqueous solution and sulphur dioxide in very low concentrations, are disinfectants.

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

Correct options are a and d.

Enzymes are protein molecules that operate as biocatalysts in the body, facilitating chemical processes. The pace of the reaction is accelerated by these catalysts.

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 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.