Hydrocarbons · JEE Main previous year questions

Match List I with List II 1 - Bromopropane is reacted with reagents in List I to give product in List II | LIST I - Reagent | LIST II - Product | | :--- | :--- | | A. $\mathrm{KOH}(\mathrm{alc})$ | I. Nitrile | | B. $\mathrm{KCN}(\mathrm{alc})$ | II. Ester | | C. ${\mathrm{AgNO}}_2$ | III. Alkene | | D. ${\mathrm{H}}_3\mathrm{CCOOAg}$ | IV. Nitroalkane | Choose the correct answer from the options given below:

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

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

Molar mass of the hydrocarbon (X) which on ozonolysis consumes one mole of ${\mathrm{O}}_3$ per mole of (X) and gives one mole each of ethanal and propanone is ___________ $\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ (Molar mass of $\mathrm{C}:12\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1},\mathrm{H}:1\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ )

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

A hydrocarbon ' X ' with formula ${\mathrm{C}}_6{\mathrm{H}}_8$ uses two moles of ${\mathrm{H}}_2$ on catalytic hydrogenation of its one mole. On ozonolysis, ' X ' yields two moles of methane dicarbaldehyde. The hydrocarbon ' X ' is:

1. A.hexa-1, 3, 5-triene
2. B.cyclohexa-1, 4-diene
3. C.cyclohexa - 1,3 - diene
4. D.1-methylcyclopenta-1, 4-diene

17 mg of a hydrocarbon (M.F. ${\mathrm{C}}_{10}{\mathrm{H}}_{16}$) takes up 8.40 mL of the ${\mathrm{H}}_2$ gas measured at $0^{\circ }\mathrm{C}$ and 760 mm of Hg. Ozonolysis of the same hydrocarbon yields $\mathrm{C}{\mathrm{H}}_3-\mathrm{CO}-\mathrm{C}{\mathrm{H}}_3$, $\mathrm{H}-\mathrm{CO}-\mathrm{H}$, $\mathrm{H}-\mathrm{CO}-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{CO}-\mathrm{CO}-\mathrm{H}$ The number of double bond/s present in the hydrocarbon is ____.

The one giving maximum number of isomeric alkenes on dehydrohalogenation reaction is (excluding rearrangement)

1. A.2-Bromo-3,3-dimethylpentane
2. B.2-Bromopropane
3. C.1-Bromo-2-methylbutane
4. D.2-Bromopentane

28.0 L of $\mathrm{C}{\mathrm{O}}_2$ is produced on complete combustion of 16.8 L gaseous mixture of ethene and methane at $25^{\circ }\mathrm{C}$ and 1 atm. Heat evolved during the combustion process is ____ kJ. Given : $\Delta {\mathrm{H}}_{\mathrm{c}}(\mathrm{C}{\mathrm{H}}_4)=-900\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$ $\Delta {\mathrm{H}}_{\mathrm{c}}({\mathrm{C}}_2{\mathrm{H}}_4)=-1400\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$

Number of hydrogen atoms per molecule of a hydrocarbon A having 85.8% carbon is ____ (Given : Molar mass of A = 84 $\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$)

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion A : Benzene is more stable than hypothetical cyclohexatriene Reason R : The delocalised $\pi$ electron cloud is attracted more strongly by nuclei of carbon atoms. In the light of the above statements, choose the correct answer from the options given below:

1. A.A is true but R is false
2. B.Both A and R are correct and R is the correct explanation of A
3. C.Both A and R are correct but R is NOT the correct explanation of A
4. D.A is false but R is true

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

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

When ethanol is heated with conc. ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$, a gas is produced. The compound formed, when this gas is treated with cold dilute aqueous solution of Baeyer's reagent, is

1. A.formaldehyde
2. B.formic acid
3. C.glycol
4. D.ethanoic acid

Arrange the following in increasing order of reactivity towards nitration A. p-xylene B. bromobenzene C. mesitylene D. nitrobenzene E. benzene Choose the correct answer from the options given below

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

Borazine, also known as inorganic benzene, can be prepared by the reaction of 3-equivalents of "$X$" with 6-equivalents of "$Y$". "$X$" and "$Y$", respectively are :

1. A.$\mathrm{B}(\mathrm{OH}{)}_3$ and $\mathrm{N}{\mathrm{H}}_3$
2. B.${\mathrm{B}}_2{\mathrm{H}}_6$ and $\mathrm{N}{\mathrm{H}}_3$
3. C.${\mathrm{B}}_2{\mathrm{H}}_6$ and $\mathrm{H}{\mathrm{N}}_3$
4. D.$\mathrm{N}{\mathrm{H}}_3$ and ${\mathrm{B}}_2{\mathrm{O}}_3$

In the presence of sunlight, benzene reacts with ${\text{Cl}}_2$ to give product, X. The number of hydrogens in X is _________.

A hydrocarbon 'X' is found to have molar mass of 80. A $10.0\text{ mg}$ of compound 'X' on hydrogenation consumed $8.40\text{ mL}$ of ${\mathrm{H}}_2$ gas (measured at STP). Ozonolysis of compound 'X' yields only formaldehyde and dialdehyde. The total number of fragments/molecules produced from the ozonolysis of compound 'X' is ___________.

Oxidation of toluene to benzaldehyde can be easily carried out with which of the following reagents?

1. A.$\mathrm{Cr}{\mathrm{O}}_3/\text{acetic acid, }{\mathrm{H}}_3{\mathrm{O}}^{+}$
2. B.$\mathrm{Cr}{\mathrm{O}}_3/\text{acetic anhydride, }{\mathrm{H}}_3{\mathrm{O}}^{+}$
3. C.$\mathrm{KMn}{\mathrm{O}}_4/\mathrm{HCl},{\mathrm{H}}_3{\mathrm{O}}^{+}$
4. D.$\mathrm{CO}/\mathrm{HCl}$, anhydrous $\mathrm{AlC}{\mathrm{l}}_3$

Which statement is NOT correct for p-toluenesulphonyl chloride?

1. A.It is known as Hinsberg's reagent.
2. B.It is used to distinguish primary and secondary amines.
3. C.On treatment with secondary amine, it leads to a product, that is soluble in alkali.
4. D.It doesn't react with tertiary amines.

At $25^{\circ }\mathrm{C}$ and $1\mathrm{atm}$ pressure, the enthalpy of combustion of benzene (l) and acetylene (g) are $-3268\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$ and $-1300\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$, respectively. The change in enthalpy for the reaction $3{\mathrm{C}}_2{\mathrm{H}}_2(\mathrm{g})\to {\mathrm{C}}_6{\mathrm{H}}_6(\mathrm{l})$, is :

1. A.$+324\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$
2. B.$+632\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$
3. C.$-632\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$
4. D.$-732\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : A mixture contains benzoic acid and napthalene. The pure benzoic acid can be separated out by the use of benzene. Reason R : Benzoic acid is soluble in hot water. In the light of the above statements, choose the most appropriate answer from the options given below.

1. A.Both A and R are true and R is the correct explanation of A.
2. B.Both A and R are true but R is NOT the correct explanation of A.
3. C.A is true but R is false.
4. D.A is false but R is true.

Given below are two statements : Statement I : The presence of weaker $\pi$-bonds makes alkenes less stable than alkanes. Statement II : The strength of the double bond is greater than that of carbon-carbon single bond. 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.

Methylation of 10 g of benzene gave 9.2 g of toluene. Calculate the percentage yield of toluene __________. (Nearest integer)

Match List - I with List - II : $$\begin{array}{llll}& \text{List - I (Chemicals)}& & \text{List - II (Use / Preparation / Constituent)}\\ \text{(a)}& \text{Alcoholic potassium hydroxide}& \text{(i)}& \text{Electrodes in batteries}\\ \text{(b)}& Pd/BaS{\mathrm{O}}_4& \text{(ii)}& \text{Obtained by addition reaction}\\ \text{(c)}& \text{BHC (Benzene hexachloride)}& \text{(iii)}& \text{Used for }\beta \text{ - elimination reaction}\\ \text{(d)}& \text{Polyacetylene}& \text{(iv)}& \text{Lindlar’s catalyst}\end{array}$$ Choose the most appropriate match :

1. A.(a) - (ii), (b) - (i), (c) - (iv), (d) - (iii)
2. B.(a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)
3. C.(a) - (iii), (b) - (i), (c) - (iv), (d) - (ii)
4. D.(a) - (ii), (b) - (iv), (c) - (i), (d) - (iii)