Chapter 23

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

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

Which of the following represents the given mode of hybridization \(s p^{2}-s p^{2}-s p-\) sp from left to right? (a) \(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{C} \equiv \mathrm{CN}\) (b) \(\mathrm{CH} \equiv \mathrm{C}-\mathrm{C} \equiv \mathrm{N}\) (c) \(\mathrm{CH}_{2}=\mathrm{C}=\mathrm{C}=\mathrm{CH}_{2}\) (d) \(\mathrm{CH}_{2}\)

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) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CHO}\)

The number and type of bonds between two carbon atoms in \(\mathrm{CaC}_{2}\) are (a) one sigma and one \(\pi\) bond (b) one sigma and two \(\pi\) bonds (c) one sigma and one and a half \(\pi\) bonds (d) one sigma bond

Which of the following has the least hindered rotation about carbon-carbon bond? (a) ethane (b) ethylene (c) acetylene (d) hexachloroethane

The \(\mathrm{Cl}-\mathrm{C}-\mathrm{Cl}\) angle in \(1,1,2,2\)-tetrachloroethene and tetrachloromethane will be about (a) \(120^{\circ}\) and \(109.5^{\circ}\) (b) \(90^{\circ}\) and \(109.5^{\circ}\) (c) \(109.5^{\circ}\) and \(90^{\circ}\) (d) \(109.5^{\circ}\) and \(120^{\circ}\)

The compound with an isopropyl group is (a) \(2,2,3,3\)-tetramethylpentane (b) 2,2 -dimethylpentane (c) \(2,2,3\)-trimethylpentane (d) 2 -methylpentane

The enolic form of acetone contains (a) 9 sigma bonds, 1 pi bond and 2 lone pair of electrons (b) 8 sigma bonds, 2 pi bonds and 2 lone pair of electrons (c) 10 sigma bonds, 1 pi bond and 1 lone pair of electrons (d) 9 sigma bonds, 2 pi bonds and 1 lone pair of electrons

How many chiral carbon atoms are present in 2,3 , 4-trichloropentane? (a) three (b) two (c) one (d) four

An optically active compound is (a) 1-bromobutane (b) \(\beta\)-bromobutyric acid (c) 2 -bromo-2-methylpropane (d) 1 -bromo-2-methylpropane

On monochlorination of 2 -methyl butane, the total number of chiral compounds is (a) 2 (b) 4 (c) 6 (d) 8

Which of the following compounds exhibit steroisomerism? (a) 2 -methylbutene-1 (b) 3 -methylbutyne-1 (c) 3 -methylbutanoic acid (d) 2 -methylbutanoic acid

The number of isomers for the compound with molecular formula \(\mathrm{C}_{2} \mathrm{BrClFI}\) is (a) 3 (b) 4 (c) 5 (d) 6

Which of the following compounds will exhibit geometrical isomerism? (a) 1-phenyl-2-butene (b) 3 -phenyl-1-butene (c) 2 -phenyl-1-butene (d) 1,1 -diphenyl-1-propene

Which of the following compounds will show geometrical isomerism? 1\. 2 -butene 2\. propene 3\. 1 -phenylpropene 4\. 2 -methylbut-2-ene (a) 1,2 (b) 3,4 (c) \(1,2,3\) (d) 1,3

How many optically active stereoisomers are possible for butan- 2,3 -diol? (a) 1 (b) 2 (c) 3 (d) 4

Which is true regarding the \(\mathrm{HOCH}_{2}-(\mathrm{CHOH})_{4}\) \(-\mathrm{CH}_{2} \mathrm{OH} ?\) (1) the number of racemic mixtures will be four for the compound. (2) the total number of optical isomers is ten and number of meso isomer is two. (3) the total number of optical isomer is sixteen and number of meso isomer is zero. (4) the optically active isomers are eight while meso isomers are two. (a) 1,2 and 3 (b) 2,3 and 4 (c) 1,2 and 4 (d) 1 and 2 only

Match the following: List I List II 1\. \(\mathrm{CH}_{3} \mathrm{COOH}\) and \(\mathrm{HCOOCH}_{3}\) (i) metamers 2\. \(\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{C} \equiv \mathrm{CH}\) and (ii) position isomers \(\mathrm{CH}_{3}-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_{3}\) 3\. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\) and (iii) tautomers \(\mathrm{CH}_{3}-\mathrm{CH}\left(\mathrm{NH}_{2}\right)-\mathrm{CH}_{3}\) 4\. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\) and \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{O}\) (iv) functional isomer The correct matching is: \(\begin{array}{llll}1 & 2 & 3 & 4\end{array}\) (a) (iii) (iv) (i) (iv) (b) (i) (ii) (iii) (iv) (c) (iii) (ii) (i) (iv) (d) (iv) (ii) (ii) (iv)

Consider the following statements: (1) racemic forms are not optically active but are resolvable (2) the presence of chiral atom is sufficient but not the necessary condition for enantiomer (3) meso compounds are inactive and are not resolvable (4) conformational enantiomers can be resolved Nuw select the conrect statements. (a) 1,2 and 3 (b) 2,3 and 4 (c) 1,2 and 4 (d) \(1,2,3\) and 4

Which is incorrectly matched? Common name \(\quad\) IUPAC name (a) Vanillin 4-hydroxy-3-methoxybenzaldehyde (b) Protocatechual- \(\quad 2,3\)-dihydroxydehyde benzaldehyde (c) Adipic acid hexanl, 6 -dioic acid (d) Pyruvic acid cis-2-methylbut-2-enoic acid

Consider the following statements about chirality: 1\. molecules which are not superimposable on their mirror images are achiral 2\. a chiral molecule can have simple axis of symmetry 3\. a carbon atom to which four different species are attached is a chiral centre. 4\. a compound whose molecules are achiral exhibits optical activity Which of the statements given above are correct? (a) 1,2 and 4 (b) 2,3 and 4 (c) 2 and 3 (d) 1 and 4

Which of the following have asymmetric carbon atoms? 1\. \(\mathrm{ClCH}_{2}-\mathrm{CH}_{2} \mathrm{Br}\) 2\. \(\mathrm{CH}_{3}-\mathrm{CHCl}_{2}\) 3\. \(\mathrm{CH}_{3}-\mathrm{CH} \mathrm{DCl}\) 4\. \(\mathrm{CH}_{2} \mathrm{Br}-\mathrm{CHOH}-\mathrm{CH}_{3}\) (a) \(1,2,3\) (b) \(1,3,4\) (c) 2,3 (d) 3,4

Identify the correct statements (a) The stereisomers which are not mirror images are diastereomers. (b) Diasteteomers have the same physical properties like melting point and solubility (c) Cis isomer has higher melting point and lower solubility than the corresponding trans isomer (d) \(\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{COCH}_{3}\) exists more in enolic form in gaseous phase or in \(\mathrm{n}\) - hexane.

For each category of compounds the minimum number of carbons required for optical isomerism to be possible is given. Find the correct match (es). (a) Alkane - 7 (b) Alkene - 6 (c) Alkyl halide \(-4\) (d) Alkadiene - 7

Which of the following are incorrect statements? (a) IUPAC names of succinic acid is ethane 1, 2 -dicarbolxylic acid. (b) Enantiomorphs possess identical biological properties. (c) Tetrahydrofuran is a heteroaromatic compound (d) Generally homologues are not isomers.

Which of the following can show geometrical isomerism ? (a) But - 1 - ene (b) But \(-2\) - ene (c) Hex \(-3\) - ene (d) 2 - Chlorobut \(-2\) - ene

Keto-enol tautomerism is observed in (a) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COCH}_{3}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}\) (c) \(\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{CO}-\mathrm{CH}_{2}-\mathrm{CO}-\mathrm{CH}_{3}\)

A compound having molecular formula \(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}\) can show (a) Functional isomerism (b) Metamerism (c) Position isomerism (d) Optical isomerism

Enol content of \(\mathrm{CH}_{3}-\mathrm{CO}-\mathrm{CH}_{2}-\mathrm{CO}-\mathrm{CH}_{3}\) will be maximum in which of the solvents? (a) Water (b) \(\mathrm{n}\) - hexane (c) \(\mathrm{CH}_{3}-\mathrm{COOH}\) (d) Aqueous \(\mathrm{HCl}\)

Match the following (a) Enantiomers (p) Equilibrium mixture (b) Diastereomers (q) Mirror images (c) Meso isomer (r) Non- mirror images (d) Tautomers (s) Non- superimposable (t) Stereo isomer

Match the following Column-I (a) \(\mathrm{CH}_{3} \mathrm{CHDT}\) (b) \(\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CH}(\mathrm{OH}) \mathrm{C}_{2} \mathrm{H}_{3}\) (c) \(\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_{3}\) Column-II (p) No optical isomer (q) Two optical isomers (r) Four optical isomers (s) Three optical isomers (t) Two asymmetric carbon atoms.

The total number of optically active isomers of the compound \(\mathrm{CH}_{2} \mathrm{OH}-\mathrm{CHBr}-\mathrm{CHOH}-\mathrm{CHBr}-\mathrm{CH}_{2} \mathrm{OH}\) is

The number of isomeric ethers corresponding to the formula \(\mathrm{C}_{5} \mathrm{H}_{12} \mathrm{O}\) is

Number of mesoforms possible for the compound \(\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{CHCl}-\mathrm{CHCl}-\mathrm{CHCl}-\mathrm{CHCl}-\mathrm{C}_{6} \mathrm{H}_{5}\) is

The number of geometrical isomers of the following alkene \(\mathrm{CH}_{3}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}-\mathrm{Cl}\) is

Find out the total number of isomeric molecules form on dichlorination of cyclopentane/

What is the number of isomers possible that may have a benzene ring and a molecular formula \(\mathrm{C}_{\gamma} \mathrm{H}_{9} \mathrm{~N} ?\)

Underlined carbon is sp \(^{3}\) hybridized in (a) \(\mathrm{CH}_{3} \mathrm{CH}=\underline{\mathrm{CH}}_{2}\) (b) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2}\) (c) \(\mathrm{CH}_{3} \mathrm{CONH}_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CN}\)

The incorrect IUPAC name is (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOC}_{2} \mathrm{H}_{5}\) ethyl butanoate (b) 3-methyl butanal (c) 2-methyl-3-pentanone 2-methyl-3-butanol

Racemic mixture is formed by mixing two (a) isomeric compounds (b) chiral compounds (c) meso compounds (d) enantiomers with chiral carbon

A similarly between optical and geometrical isomerism is that (a) if in a compound, one is present then so is the other. (b) each forms equal number of isomers for a given compound (c) both are included in stereoisomerism (d) they have no similarly

Which of the following does not show geometrical isomerism? (a) 1,1 -dichloro-1-pentene (b) 1,2 -dichloro- 1 -pentene (c) 1,3 -dichloro-1-pentene (d) 1,4 -dichlroro-2-pentene

The IUPAC name of \(\mathrm{CH}_{3} \mathrm{COCH}\left(\mathrm{CH}_{3}\right)_{2}\) is (a) 4-methyl isopropyl ketone (b) 3 -methylbutan-2-one (c) isopropylmethyl ketone (d) 2-methylbutan-3-one

Which one of the following does not have spª hybridized carbon? (a) acetone (b) acetic acid (c) acetonitrile (d) acetamide

Which of the following will have a meso isomer also? (a) 2 -chlorobutane (b) 2,3 -dichlorobutane (c) 2,3 -dichloropentane (d) 2 -hydroxypropanoic acid

For which of the following parameters of the structural isomers \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\) and \(\mathrm{CH}_{3} \mathrm{OCH}_{3}\) would be expected to have the same values? (Assume ideal behaviour)[2004] (a) heat of vaporization (b) vapour pressure at the same temperature (c) boiling points (d) gaseous densities at the same temperature and pressure

Of the five isomeric hexanes, the isomer which can give two monochlorination compound is [2005] (a) n-hexane (b) 2,3 -dimethylbutane (c) 2,2 -dimethylbutane (d) 2 -methylpentane

Which one of the following conformations of cyclohexane is chiral? (a) rigid (b) chair (c) boat (d) twist boat