unit-iii-poc-iii

Which of the following shows atropisomerism?

• Toluene

• Biphenyl

• Benzene

• Ethylbenzene

Which of the following reactions produce different stereoisomers selectively?

• Stereospecific

• Stereoselective

• Regioselective

• Chemoselective

Which conformer of n-butane is most stable?

• Fully eclipsed

• Gauche

• Anti

• Half-chair

Which heterocyclic compound is most aromatic?

• Pyrrole

• Thiophene

• Furan

• Indole

Which of the following contains a nitrogen atom in the ring?

• Thiophene

• Furan

• Pyrrole

• Benzofuran

Which reagent is typically used in the synthesis of pyrrole?

• Acetylene and ammonia

• 1,4-dicarbonyl compounds and ammonia

• Phenol and acetic acid

• Ethyl acetate

Which of the following reactions is common for furan, thiophene, and pyrrole?

• Friedel-Crafts acylation

• Electrophilic substitution

• Hydrogenation

• Elimination

The order of aromaticity is:

• Pyrrole > Furan > Thiophene

• Thiophene > Pyrrole > Furan

• Furan > Thiophene > Pyrrole

• Thiophene > Furan > Pyrrole

Pyrrole is more reactive than benzene toward electrophiles because:

• It has less aromatic character

• Nitrogen donates electron density

• It is non-aromatic

• Nitrogen withdraws electrons

Thiophene is used in the synthesis of:

• Antipyretics

• Anticonvulsants

• Antitubercular drugs

• Antifungals