Hydrocarbons · JEE Main previous year questions

$R_f$ value for 2-methylpropene in a solvent system (Ethyl acetate + ether) is 0.42. 2-methylpropene is treated with dilute ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ to give major organic product (X). $R_f$ value for (X) in the same solvent system under identical condition will be:

1. A.0.42
2. B.0.82
3. C.0.62
4. D.0.12

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

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

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

Match the LIST-I with LIST-II $$\begin{array}{ll}\text{List-I}& \text{List-II}\\ \text{Reaction}& \text{Mechanism}\\ \text{A. Williamson Synthesis}& \text{I. Electrophilic addition}\\ \text{B. Friedel Craft Reaction}& \text{II. Free radical substitution}\\ \text{C. Bromination of vinyl benzene}& \text{III. Nucleophilic substitution}\\ \text{D. Chlorination of toluene in light}& \text{IV. Electrophilic substitution}\end{array}$$ Choose the correct answer from the options given below:

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

The compound (X) on (i) on heating in the presence of anhydrous $\mathrm{AlC}{\mathrm{l}}_3$ and $\mathrm{HCl}$ gas gives 2,4-dimethyl pentane (ii) aromatization gives toulene and (iii) cyclisation gives methyl cyclohexane The correct name of compound (X) is :

1. A.Hept-2-ene
2. B.Hept-1,3,5-triene
3. C.Heptane
4. D.Hept-2,4,6-triene

Identify the correct statements : The presence of $-{\text{NO}}_2$ group in benzene ring A. activates the ring towards electrophilic substitutions. B. deactivates the ring towards electrophilic substitutions. C. activates the ring towards nucleophilic substitutions. D. deactivates the ring towards nucleophilic substitutions. Choose the correct answer from the options given below :

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

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

Given below are two statements : Statement I : Benzene is nitrated to give nitrobenzene, which on further treatment with $\mathrm{C}{\mathrm{H}}_{3}COCl/AlC{\mathrm{l}}_3$ will give [structure: benzene ring with $\mathrm{COC}{\mathrm{H}}_3$ and $\mathrm{N}{\mathrm{O}}_2$ meta to each other] Statement II : $-\mathrm{N}{\mathrm{O}}_2$ group is a $m$-directing, and deactivating group. In the light of the above statements, choose the most appropriate answer from the options given below

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

Given below are two statements: Statement (I) : Molal depression constant $K_f$ is given by $\frac{{\mathrm{M}}_1\mathrm{R}{\mathrm{T}}_f}{\Delta {\mathrm{S}}_{\mathrm{fus}}}$, where symbols have their usual meaning. Statement (II) : $K_f$ for benzene is less than the $K_f$ for water. In the light of the above statements, choose the most appropriate answer from the options given below :

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

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

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

$\mathrm{X}\mathrm{g}$ of nitrobenzene on nitration gave $4.2\mathrm{g}$ of $\mathrm{m}$-dinitrobenzene. $\mathrm{X}=$___________g. (nearest integer) $[\text{Given : molar mass (in }{\mathrm{gmol}}^{-1})\mathrm{C}:12,\mathrm{H}:1,\mathrm{O}:16,\mathrm{N}:14]$

Given below are two statements : Statement (I): On nitration of m-xylene with $\mathrm{HN}{\mathrm{O}}_3,{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ followed by oxidation, 4-nitrobenzene-1,3-dicarboxylic acid is obtained as the major product. Statement (II) : $-\mathrm{C}{\mathrm{H}}_3$ group is o/p-directing while $-\mathrm{N}{\mathrm{O}}_2$ group is m-directing group. 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

Isomeric hydrocarbons $\to$ negative Baeyer's test (Molecular formula ${\mathrm{C}}_9{\mathrm{H}}_{12}$) The total number of isomers from above with four different non-aliphatic substitution sites is -

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

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

The hydrocarbon (X) with molar mass $80\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ and $90\%$ carbon has ____ degree of unsaturation.

The incorrect statement regarding ethyne is

1. A.The carbon-carbon bond in ethyne is weaker than that in ethene
2. B.Both carbons are $\mathrm{sp}$ hybridised
3. C.The $\mathrm{C}-\mathrm{C}$ bond in ethyne is shorter than that in ethene
4. D.Ethyne is linear

Given below are two statements : Statement (I) : All the following compounds react with p-toluenesulfonyl chloride. ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N}{\mathrm{H}}_2({\mathrm{C}}_6{\mathrm{H}}_5{)}_2\mathrm{NH}({\mathrm{C}}_6{\mathrm{H}}_5{)}_3\mathrm{N}$ Statement (II) : Their products in the above reaction are soluble in aqueous $\mathrm{NaOH}$. In the light of the above statements, choose the correct answer from the options given below :

1. A.Statement I is false but Statement II is true
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 true but Statement II is false

1. A.$\text{(III)}>\text{(IV)}>\text{(II)}>\text{(I)}$
2. B.$\text{(III)}>\text{(I)}>\text{(II)}>\text{(IV)}$
3. C.$\text{(II)}>\text{(IV)}>\text{(III)}>\text{(I)}$
4. D.$\text{(IV)}>\text{(I)}>\text{(II)}>\text{(III)}$

Common name of Benzene - 1,2 - diol is -

1. A.catechol
2. B.quinol
3. C.o-cresol
4. D.resorcinol

$10\text{ mL}$ of gaseous hydrocarbon on combustion gives $40\text{ mL}$ of $\mathrm{C}{\mathrm{O}}_2(\mathrm{g})$ and $50\text{ mL}$ of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is ________ .

The correct order of reactivity in electrophilic substitution reaction of the following compounds is : A: benzene, B: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}{\mathrm{H}}_3$, C: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{Cl}$, D: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N}{\mathrm{O}}_2$

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