Chapter 23

The IUPAC name of \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COCl}\) is (a) benzoyl chloride (b) benzene chloroketone (c) benzene carbonyl chloride (d) chlorophenyl ketone

In the reaction, \(\mathrm{CH}_{3} \mathrm{CHO}+\mathrm{HCN} \longrightarrow \mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CN}\) a chiral centre is produced. This product would be (a) racemic mixture (b) meso compound (c) dextrorotatory (d) laevorotatory

Optical activity is measured by (a) refractometer (b) tracer technique (c) spectrograph (d) polarimeter

The compound having only primary hydrogen atoms is (a) isobutene (b) 2,3 -dimethyl but-2-ene (c) cyclohexane (d) propyne

Which of the following shows geometrical isomerism? (a) but-1-ene (b) but-2-ene (c) 2,3 -dichlorobutane (d) ethene

The number of optically active isomers of tartaric acid is CC(O)C(=O)O (a) 2 (b) 3 (c) 4 (d) 1

The compound in which \(\mathrm{C}\) uses only its \(\mathrm{sp}^{3}\) hybrid orbitals for bond formation is (a) \(\mathrm{HCOOH}\) (b) \(\left(\mathrm{NH}_{2}\right)_{2} \mathrm{CO}\) (c) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}\) (d) \(\mathrm{CH}_{3} \mathrm{CHO}\)

Number of isomers which can be obtained theoretically from monochlorination of 2 -methylbutane are (a) 2 (b) 3 (c) 4 (d) 5

An organic molecule necessarily shows optical activity if it (a) is non-superimposable on its mirror image (b) is superimposable on its mirror image (c) contains asymmetric carbon atoms (d) is non-polar

The C-H bond distance is longest in (a) \(\mathrm{C}_{2} \mathrm{H}_{2}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{4}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{6}\) (d) \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{Br}_{2}\)

How many structural isomers of \(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}\) that are ethers? (a) 1 (b) 2 (c) 3 (d) 4

Which of the following has zero dipole moment? (a) 1 -butene (b) cis-2-butene (c) trans-2-butene (d) 2 methyl-1-propene

The most stable conformation of ethylene glycol is (a) anti (b) gauche (c) fully eclipsed (d) partially eclipsed

The total number of isomers for \(\mathrm{C}_{4} \mathrm{H}_{8}\) are (a) 8 (b) 7 (c) 6 (d) 5

\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{C} \equiv \mathrm{N}\) and \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N} \sqsupseteq \mathrm{C}\) are which type of isomers? (a) tautomerism (b) position (c) functional (d) linkage

How many stereoisomers are there for tartaric acid? (a) 3 (b) 4 (c) 5 (d) 0

The number of enantiomers of the compound \(\mathrm{CH}_{3} \mathrm{CHBrCHBrCOOH}\) is (a) 1 (b) 2 (c) 3 (d) 4

Which of the following compounds will show metamerism? (a) \(\mathrm{CH}_{3}-\mathrm{O}-\mathrm{C}_{2} \mathrm{H}_{3}\) (b) \(\mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{3}\) (c) \(\mathrm{CH}_{3}-\mathrm{CO}-\mathrm{C}_{2} \mathrm{H}_{5}\) (d) \(\mathrm{C}_{2} \mathrm{H}_{5}-\mathrm{S}-\mathrm{C}_{2} \mathrm{H}_{5}\)

What will be the IUPAC name of given compound? CCC(C)CC(CC)C(C)C (a) 2,5 -diethyl-4-methylhexane (b) \(3,3,6\)-trimethyloctane (c) \(2,5,6\)-trimethyloctane (d) 3,5 -dimethyl-6-ethylheptane

In the boat conformation of cyclohexane, the most destabilizing interaction is (a) eclipsing (b) flagpole-flagpole (c) 1,3 -diaxial (d) 1,3 -diequatorial

(+)-mandelic acid has a specific rotation of \(+158^{\circ}\). What would be the observed specific rotation of a mixture containing \(25 \%\) (-)-mandelic acid and \(75 \%\) (+)-mandelic acid? (a) \(+79^{\circ}\) (b) \(-118.5^{\circ}\) (c) \(-79^{\circ}\) (d) \(+118.5^{\circ}\)

The number of geometrical isomers of \(\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}=\mathrm{CHCl}\) are (a) 4 (b) 6 (c) 8 (d) 10

\(\mathrm{C}_{3} \mathrm{H}_{9} \mathrm{~N}\) cannot represent (a) quaternary salt (b) \(1^{\circ}\) amine (c) \(2^{\circ}\) amine (d) \(3^{\circ}\) amine

Which of the following is optically active? (a) butane (b) 2 -methylpentane (c) 4-methylpentane (d) 3-methylheptane

The hybridization of carbon atoms in C-C single bond of \(\mathrm{HC} \equiv \mathrm{C}-\mathrm{CH}=\mathrm{CH}_{2}\) is (a) \(\mathrm{sp}^{3}-\mathrm{sp}^{3}\) (b) \(\mathrm{sp}^{2}-\mathrm{sp}^{3}\) (c) \(\mathrm{sp}^{2}-\mathrm{sp}\) (d) \(\mathrm{sp}^{3}-\mathrm{sp}\)

Number of \(\pi\)-electrons in cyclobutadienyl anion \(\left(\mathrm{C}_{4} \mathrm{H}_{4}\right)^{2-}\) is (a) 2 (b) 4 (c) 6 (d) 8

The \(\mathrm{R}\) and \(\mathrm{S}\) enantiomers of an optically active compound differs in (a) their optical rotation of plane polarized light (b) their reactivity with a chiral reagents (c) their solubility in achiral reagents (d) their melting points

The number of primary amines of formula \(\mathrm{C}_{4} \mathrm{H}_{11} \mathrm{~N}\) are (a) 2 (b) 3 (c) 4 (d) 5

The C-C bond length of the following molecules are in the order (a) \(\mathrm{C}_{2} \mathrm{H}_{6}>\mathrm{C}_{2} \mathrm{H}_{4}>\mathrm{C}_{6} \mathrm{H}_{6}>\mathrm{C}_{2} \mathrm{H}_{2}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{2}<\mathrm{C}_{2} \mathrm{H}_{4}<\mathrm{C}_{6} \mathrm{H}_{6}<\mathrm{C}_{2} \mathrm{H}_{6}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{6}>\mathrm{C}_{2} \mathrm{H}_{2}>\mathrm{C}_{6} \mathrm{H}_{6}>\mathrm{C}_{2} \mathrm{H}_{4}\) (d) \(\mathrm{C}_{2} \mathrm{H}_{4}>\mathrm{C}_{2} \mathrm{H}_{6}>\mathrm{C}_{2} \mathrm{H}_{2}>\mathrm{C}_{6} \mathrm{H}_{6}\)

An organic molecule necessarily shows optical activity if it (a) contains asymmetric carbon atoms (b) is non-planar (c) is non-superimposable on its mirror image (d) is superimposable on its mirror image

The maximum number of carbon atoms arranged linearly in the molecule, \(\mathrm{CH}_{3}-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}=\mathrm{CH}_{2}\) are (a) 3 (b) 4 (c) 5 (d) 6

The IUPAC name of cinnamic acid is (a) phenylpropanoic acid (b) 3 -phenylprop-2-enoic acid (c) 3-phenylpropanoic acid (d) benzene-1, 4 -dicarboxylic acid

The IUPAC name of the compound \(\mathrm{CH}_{3}-\mathrm{C}\left(\mathrm{CH}_{3}\right)_{2}-\mathrm{CH}=\mathrm{C}\left(\mathrm{CH}_{3}\right)_{2}\) is (a) \(1,1,3,3\)-tetramethyl-but-1-ene (b) \(1,3,3\)-trimethyl-pent- 2 -ene (c) \(2,2,4\)-trimethylbut-4-ene (d) \(2,4,4\)-trimethylpent-2-ene

One recently discovered allotrope of carbon \(\left(\mathrm{C}_{60}\right)\) is commonly known as (a) fluorine (b) fluorene (c) freon (d) fullerene

The optically active tartaric acid is named as \(\mathrm{D}-(+)-\) tartaric acid because it has a positive (a) optical rotation and is derived from D-glucose (b) \(\mathrm{pH}\) in an organic solvent (c) optical rotation and is derived from D-(+)glyceraldehyde (d) optical rotation only when substituted by deuterium

Keto \(-\) enol tautomerism is observed in : (a) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OCH}_{3}\) (c) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COCH}_{2} \mathrm{COOH}\) (d) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COC}_{6} \mathrm{H}_{5}\)

Maximum enol content is observed in (a) \(\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{COOC}_{2} \mathrm{H}_{5}\) (b) O=C1C=CC=CC1 (c) \(\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{COCH}_{3}\) (d) \(\mathrm{CH}_{3} \mathrm{COCH}_{3}\)

Assign the IUPAC name to \(\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CH}\right]_{3}\) COH. (a) 3-(2-methylethyl)-3(1-methylethyl) pentan-2-ol (b) tris-(1-methylpropyl)methanol (c) 2,4 -dimethyl-3 (1-methylethyl) pentan- \(2-\mathrm{ol}\) (d) 3-(1-methylethyl)-2, 4-dimethylpentan-3-ol

Which will exhibit geometrical isomerism here? (a) \(\mathrm{A}_{2} \mathrm{C}=\mathrm{CAB}\) (b) \(\mathrm{A}_{2} \mathrm{C}=\mathrm{CB}_{2}\) (c) \(\mathrm{ABC}=\mathrm{CAB}\) (d) \(\mathrm{ABC}=\mathrm{CX}_{2}\)

2-methylpenta-2,3-diene is achiral as it has (a) a centre of symmetry (b) a plane of symmetry (c) a \(\mathrm{C}_{2}\) axis of symmetry (d) both centre and a plane of symmetry

The bond between carbon atom (1) and carbon atom (2) in compound \(\mathrm{N} \equiv \mathrm{C}-\mathrm{CH}=\mathrm{CH}_{2}\) involves the hybridization (a) \(\mathrm{sp}^{2}\) and \(\mathrm{sp}^{2}\) (b) \(\mathrm{sp}^{3}\) and \(\mathrm{sp}\) (c) sp and \(\mathrm{sp}^{2}\) (d) sp and sp

The total number of optically active isomers for \(\mathrm{CH}_{2} \mathrm{OH}(\mathrm{CHOH})_{3} \mathrm{CHO}\) are (a) 16 (b) 8 (c) 4 (d) 2

Total number of isomers and optically active compounds in the isomers of \(\mathrm{C}_{3} \mathrm{H}_{5} \mathrm{Br}\) are (a) 6,4 (b) 5,3 (c) 3,5 (d) 8,3

On monochlorination of n-pentane, the number of isomers formed is are (a) 4 (b) 3 (c) 2 (d) 1

The number of possible open chain (acyclic) isomeric compounds for molecular formula \(\mathrm{C}_{5} \mathrm{H}_{10}\) would be (a) 5 (b) 6 (c) 7 (d) 4

Assign the IUPAC name for the following compound. (a) 3,4 -dichloroazobenzene (b) (4-chlorophenyl) (3-chlorophenyl) diazene (c) 3,4 -bis(chlorophenyl) diazene (d) (3-chlorophenyl) (4-chlorophenyl) diazene

The IUPAC name of the compound is (a) 6-oxo-2-methyl hex-3-enamide (b) 6-keto-2-methyl hexanamide (c) 2 -carbamoylhexanal (d) 2 -carbamoylhex \(-3\)-enal

A compound with molecular formula \(\mathrm{C}_{7} \mathrm{H}_{16}\) shows optical isomerism. The compound will be (a) 2-methylhexane (b) 2,2 -dimethylpentane (c) 2,3 -dimethylpentane (d) none of these

In the compound, \(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{C} \equiv \mathrm{CH}\), the \(\mathrm{C}_{2}-\mathrm{C}_{3}\) bond is of the type (a) \(\mathrm{sp}-\mathrm{sp}^{2}\) (b) \(s p^{3}-s p^{3}\) (c) \(\mathrm{sp}-\mathrm{sp}^{3}\) (d) \(\mathrm{sp}^{2}-\mathrm{sp}^{3}\)

An organic compound \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}\) is found to be optically active. Which of the following is correct structure of the given compound? (a) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCHO}\) (b) \(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{3}\) (c) \(\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{CH}_{3}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CHO}\)