General Organic Chemistry & Isomerism · JEE Main previous year questions

1. A.6
2. B.4
3. C.3
4. D.5

n-Butane on monochlorination under photochemical condition gives an optically active compound "P". "P" on further chlorination gives dichloro compounds. The number of dichloro compounds obtained (ignore stereoisomers) is :

1. A.3
2. B.4
3. C.5
4. D.6

Given below are two statements: Statement I: 2,6-diethylcyclohexanone and 6-methyl-2-n-propylcyclohexanone are metamers. Statement II: 2,2,6,6 - tetramethylcyclohexanone exhibits keto-enol tautomerism. In the light of the above statements, choose the correct answer from the options given below

1. A.Both Statement I and Statement II are true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Given below are two statements: Statement I: 3-phenylpropene reacts with $\mathrm{HBr}$ and gives secondary alkyl bromide having a chiral carbon atom as the major product. Statement II: Aryl chlorides and aryl cyanides can be prepared by Sandmeyer reaction as well as Gattermann reaction. In the light of the above statements, choose the correct answer from the options given below

1. A.Both Statement I and Statement II are true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Given below are two statements : Statement I : A mixture of ${\text{C}}_{12}{\text{H}}_{22}{\text{O}}_{11}$ (sugar) and $\text{NaCl}$ can be separated by dissolving sugar in alcohol, due to differential solubility. Statement II : Rose essence from rose petals is seperated by steam distillation due to its high volatility and insolubility in ${\text{H}}_2\text{O}$. In the light of the above statements, choose the correct answer from the options given below :

1. A.Both Statement I and Statement II are true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Given below are two statements: Statement I: On the basis of inductive effect, the order of stability of alkyl carbanions is ${\text{CH}}_3^{-}>{\text{CH}}_3\text{–}{\text{CH}}_2^{-}>({\text{CH}}_3{)}_2{\text{CH}}^{-}>({\text{CH}}_3{)}_3{\text{C}}^{-}$. Statement II: Allyl and benzyl carbanions are more stabilised by inductive effect and not by resonance effect. In the light of the above statements, choose the correct answer from the options given below

1. A.Both Statement I and Statement II are correct
2. B.Both Statement I and Statement II are incorrect
3. C.Statement I is correct but Statement II is incorrect
4. D.Statement I is incorrect but Statement II is correct

IUPAC name of the some alkenes are given below. Find out the correct stability order. A. 2-Methylbut-2-ene B. cis-But-2-ene C. 2, 3-Dimethylbut-2-ene D. Prop-1-ene Choose the $\underline{\text{correct}}$ answer from the options given below :

1. A.$\mathrm{C}>\mathrm{A}>\mathrm{B}>\mathrm{D}$
2. B.$\mathrm{C}>\mathrm{A}>\mathrm{D}>\mathrm{B}$
3. C.$\mathrm{B}>\mathrm{D}>\mathrm{A}>\mathrm{C}$
4. D.$\mathrm{A}>\mathrm{B}>\mathrm{C}>\mathrm{D}$

Identify the correct IUPAC name of hydrocarbon ($x$) containing three primary carbon atoms and with molar mass $72\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$.

1. A.1, 1 - Dimethylcyclopropane
2. B.2, 2 - Dimethylpropane
3. C.2 - Methylbutane
4. D.n-pentane

In Rutherford's alpha-particle scattering experiment, only a few alpha particles rebound back because A. The size of gold nucleus is very small as compared to the size of gold atom. B. Alpha particle and gold nucleus have equal charge. C. The impact parameter is minimum for a few alpha particles. D. A few alpha particles have very high kinetic energy. E. Only a few alpha particles undergo head-on collision with the nuclei. Choose the correct answer from the options given below :

1. A.A, B Only
2. B.B, E Only
3. C.C, D Only
4. D.A, C, E Only

Given below are two statements : Statement (I) : Benzyl chloride reacts faster in ${\mathrm{S}}_{\mathrm{N}}1$ mechanism than ethyl chloride. Statement (II) : Ethyl carbocation intermediate is less stabilized by hyperconjugation than benzyl carbocation by resonance. In the light of the above statements, choose the correct answer from the options given below :

1. A.Both Statement I and Statement II are true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

1. A.Predominantly at "r"
2. B."r" and "u"
3. C."p" and "s"
4. D.Predominantly at "u"

Complete combustion of $\mathrm{X}\mathrm{g}$ of an organic compound gave $0.25\mathrm{g}$ of $\mathrm{C}{\mathrm{O}}_2$ and $0.12\mathrm{g}$ of ${\mathrm{H}}_2\mathrm{O}$. If the $\%$ of carbon is $25\%$ and of hydrogen is $4.89\%$, then $\mathrm{X}=$ ____ $\times 10^{-3}\mathrm{g}$. (Nearest integer) (Molar mass of C, H and O are 12, 1 and $16\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ respectively.)

1. A.273
2. B.27
3. C.2730
4. D.227

1. A.Both Statement I and Statement II are true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

1. A.
2. B.
3. C.
4. D.

$\mathrm{X}$ is the number of geometrical isomers exhibited by $\left[\mathrm{Pt}\left({\mathrm{NH}}_3\right)\left({\mathrm{H}}_2\mathrm{O}\right)\mathrm{BrCl}\right]$. $\mathrm{Y}$ is the number of optically inactive isomer(s) exhibited by ${\left[{\mathrm{CrCl}}_2(\mathrm{ox}{)}_2\right]}^{3-}$ $\mathrm{Z}$ is the number of geometrical isomers exhibited by $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_3{\left({\mathrm{NO}}_2\right)}_3\right]$. The value of $\mathrm{X}+\mathrm{Y}+\mathrm{Z}$ is ____ .

1. A.B and C Only
2. B.A and B Only
3. C.A and C Only
4. D.A, C and D only

Arrange the following carbanions in the decreasing order of stability. I. $p-\mathrm{Br}-{\mathrm{C}}_6{\mathrm{H}}_4-\stackrel{\ominus }{\ddot{\mathrm{C}}}{\mathrm{H}}_2$ II. ${\mathrm{C}}_6{\mathrm{H}}_5-\stackrel{\ominus }{\ddot{\mathrm{C}}}{\mathrm{H}}_2$ III. $p-\mathrm{C}{\mathrm{H}}_3\mathrm{O}-{\mathrm{C}}_6{\mathrm{H}}_4-\stackrel{\ominus }{\ddot{\mathrm{C}}}{\mathrm{H}}_2$ IV. $p-\mathrm{CHO}-{\mathrm{C}}_6{\mathrm{H}}_4-\stackrel{\ominus }{\ddot{\mathrm{C}}}{\mathrm{H}}_2$ V. $p-\mathrm{C}{\mathrm{H}}_3-{\mathrm{C}}_6{\mathrm{H}}_4-\stackrel{\ominus }{\ddot{\mathrm{C}}}{\mathrm{H}}_2$ Choose the correct answer from the options given below :

1. A.I > II > IV > V > III
2. B.IV > II > I > III > V
3. C.I > IV > II > V > III
4. D.IV > I > II > V > III

In Dumas method for estimation of nitrogen, $0.50\mathrm{g}$ of an organic compound gave $70\mathrm{mL}$ of nitrogen collected at $300\mathrm{K}$ and $715\mathrm{mm}$ pressure. The percentage of nitrogen in the organic compound is ____ %. (Aqueous tension at $300\mathrm{K}$ is $15\mathrm{mm}$ ).

Consider all the structural isomers with molecular formula ${\mathrm{C}}_5{\mathrm{H}}_{11}\mathrm{Br}$ are separately treated with $\mathrm{KOH}(\mathrm{aq})$ to give respective substitution products, without any rearrangement. The number of products which can exhibit optical isomerism from these is ____ .

Given below are two statements : Statement I : Phenol on treatment with $\mathrm{CHC}{\mathrm{l}}_3$ /aq. KOH under refluxing condition, followed by acidification produces $p$-hydroxy benzaldehyde as the major product and $o$-hydroxy benzaldehyde as the minor product. Statement II : The mixture of $p$-hydroxybenzaldehyde and $o$-hydroxybenzaldehyde can be easily separated through steam distillation. In the light of the above statements, choose the correct answer from the options given below

1. A.Statement I is true but Statement II is false
2. B.Both Statement I and Statement II are true
3. C.Both Statement I and Statement II are false
4. D.Statement I is false but Statement II is true

The correct order of reactivity of $\mathrm{C}{\mathrm{H}}_3\mathrm{Br}$ in methanol with the following nucleophiles is ${\mathrm{F}}^{-},{\mathrm{I}}^{-},{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}$ and ${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{O}}^{-}$

1. A.${\mathrm{I}}^{-}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{F}}^{-}$
2. B.${\mathrm{I}}^{-}>{\mathrm{F}}^{-}>{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}$
3. C.${\mathrm{I}}^{-}>{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{F}}^{-}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}$
4. D.${\mathrm{I}}^{-}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{F}}^{-}>{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{O}}^{-}$

Identify correct statements from the following : A. Propanal and propanone are functional isomers. B. Ethoxyethane and methoxypropane are metamers. C. But-2-ene shows optical isomerism. D. But-1-ene and but-2-ene are functional isomers. E. Pentane and 2, 2-dimethyl propane are chain isomers. Choose the correct answer from the options given below :

1. A.A, B and E only
2. B.A, B and C only
3. C.C, D and E only
4. D.B, C and D only

Match List - I with List - II. $$\begin{array}{ll}\text{List - I (Pair of Compounds)}& \text{List - II (Type of Isomers)}\\ \text{A. 2-Methylpropene and but-1-ene}& \text{I. Stereoisomers}\\ \text{B. Cis-but-2-ene and trans-but-2-ene}& \text{II. Position isomers}\\ \text{C. 2-Butanol and diethyl ether}& \text{III. Chain isomers}\\ \text{D. But-1-ene and but-2-ene}& \text{IV. Functional group isomers}\end{array}$$ Choose the correct answer from the options given below :

1. A.A-III, B-I, C-IV, D-II
2. B.A-II, B-I, C-IV, D-III
3. C.A-I, B-IV, C-III, D-II
4. D.A-III, B-I, C-II, D-IV

Given below are four compounds : (a) n-propyl chloride       (b) iso-propyl chloride (c) sec-butyl chloride      (d) neo-pentyl chloride Percentage of carbon in the one which exhibits optical isomerism is :

1. A.46
2. B.40
3. C.52
4. D.56

Match the LIST-I with LIST-II $$\begin{array}{ll}\text{LIST-I}& \text{LIST-II}\\ \text{A. Carbocation}& \text{I. Species that can supply a pair of electrons.}\\ \text{B. C-Free radical}& \text{II. Species that can receive a pair of electrons.}\\ \text{C. Nucleophile}& \text{III. }\mathrm{s}{\mathrm{p}}^2\text{ hybridized carbon with empty p-orbital.}\\ \text{D. Electrophile}& \text{IV. }\mathrm{s}{\mathrm{p}}^2/s{\mathrm{p}}^3\text{ hybridized carbon with one unpaired electron.}\end{array}$$ Choose the \textbf{correct} answer from the options given below:

1. A.A-IV, B-II, C-III, D-I
2. B.A-II, B-III, C-I, D-IV
3. C.A-III, B-IV, C-I, D-II
4. D.A-III, B-IV, C-II, D-I