JEE Chemistry Hydrocarbons MCQs Set C

Question:

• a) A – (r), B – (p), C – (s), D – (q)
• b) A – (p), B – (s), C – (r), D – (q)
• c) A – (s), B – (q), C – (p), D – (r)
• d) A – (q), B – (p), C – (s), D – (r)

Answer: A – (r), B – (p), C – (s), D – (q)

Question:

• a) A – (r), B – (p), C – (s), D – (q)
• b) A – (p), B – (q), C – (r), D – (s)
• c) A – (q), B – (p), C – (s), D – (r)
• d) A – (s), B – (p), C – (r), D – (s)

Answer: A – (r), B – (p), C – (s), D – (q)

Question:

• a) A – (r), B – (s), C – (p), D – (q)
• b) A – (s), B – (r), C – (q), D – (p)
• c) A – (q), B – (p), C – (s), D – (r)
• d) A – (r), B – (s), C – (q), D – (p)

Answer: A – (r), B – (s), C – (p), D – (q)

Question:

• a) A – (q), B – (r), C – (s), D – (p)
• b) A – (s), B – (r), C – (q), D – (p)
• c) A – (r), B – (p), C – (q), D – (s)
• d) A – (q), B – (p), C – (s), D – (r)

Answer: A – (q), B – (r), C – (s), D – (p)

Question:

• a) A – (s), B – (r), C – (q), D – (p)
• b) A – (s), B – (r), C – (p), D – (q)
• c) A – (r), B – (s), C – (p), D – (q)
• d) A – (r), B – (s), C – (q), D – (p)

Answer: A – (s), B – (r), C – (q), D – (p)

Question:

• a) A - (q), B - (s), C - (p); D - (r)
• b) A - (r), B - (p), C - (s); D - (q)
• c) A - (s), B - (q), C - (r); D - (p)
• d) A - (p), B - (r), C - (q); D - (s)

Answer: A - (q), B - (s), C - (p); D - (r)

Question:

• a) A - (p, s), B - (p, r), C - (s), D - (q, r)
• b) A - (p, r), B - (p, s), C - (s), D - (q, r)
• c) A - (p, s), B - (s), C - (p, r), D - (q, r)
• d) A - (q, r), B - (p, r), C - (s), D - (p, s)

Answer: A - (p, s), B - (p, r), C - (s), D - (q, r)

Question:

• a) A – (s), B – (p, r), C – (q, r), D – (r)
• b) A – (r), B – (p, r), C – (q, r), D – (s)
• c) A – (p, r), B – (s), C – (q, r), D – (r)
• d) A – (s), B – (p, r), C – (r), D – (q, r)

Answer: A – (s), B – (p, r), C – (q, r), D – (r)

Question:

Statement-1 : 1-Butene on reaction with HBr in the presence of a peroxide produces 1-bromobutane.
Statement-2 : It involves the free radical mechanism.

• a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
• b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct

Answer: Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question:

Statement-1 : Iodination of alkanes is reversible.
Statement-2 : Iodination is carried out in presence of iodic acid.

• a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• b) Assertion is correct, reason is correct; reason is a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct

Answer: Assertion is correct, reason is correct; reason is not a correct explanation for assertion

Question:

Statement-1 : CH₄ does not react with Cl2 in dark.
Statement-2 : Chlorination of CH₄ takes place in sunlight.

• a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• b) Assertion is correct, reason is correct; reason is a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct

Answer: Assertion is correct, reason is correct; reason is not a correct explanation for assertion

Question:

Statement-1 : All the hydrogen atoms in CH₂ = C = CH₂ lie in one plane.
Statement-2 : Carbon atoms are sp² and sp hybridized

• a) Assertion is incorrect, reason is correct.
• b) Assertion is correct, reason is correct; reason is a correct explanation for assertion
• c) None of these
• d) Assertion is incorrect, reason is correct

Answer: Assertion is incorrect, reason is correct.

Question:

• a) Assertion is correct, reason is incorrect
• b) Assertion is incorrect, reason is correct
• c) Assertion is correct, reason is correct; reason is not a orrect explanation for assertion
• d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: Assertion is correct, reason is incorrect

Question: In cyclopropane, cyclobutane and cyclohexane, the common group is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The number of primary, secondary, tertiary and quaternary carbons in neopentane are respectively

• a) 4, 0, 0 and 1
• b) 4, 3, 2 and 1
• c) 5, 0, 0 and 1
• d) 4, 0, 1 and 1

Answer: 4, 0, 0 and 1

More Questions.........................................

Question:

• a) 3, 4, 4–Trimethyl octane
• b) 3, 4, 4–Trimethyl heptane
• c) 2–Ethyl, 3,3–dimethyl heptane
• d) 2–Butyl, 2 methyl,3–ethyl butane

Answer: 3, 4, 4–Trimethyl octane

Question: Which one of the following has the lowest boiling point?

• a) 2-methyl propane
• b) 2-methylbutane
• c) 2, 2-dimethyl propane
• d) n-pentane

Answer: 2-methyl propane

Question:  Arrange the following in decreasing order of their boiling points.

(A) n–butane   (B) 2-methylbutane
(C) n-pentane  (D) 2, 2–dimethylpropane

• a) C > B > D > A
• b) B > C > D > A
• c) A > B > C > D
• d) D > C > B > A

Answer: C > B > D > A

Question: When neo-pentyl bromide is subjected to Wurtz reaction, the product formed is

• a) 2,2,5,5-tetramethylhexane
• b) 2,2,3,3-tetramethylhexane
• c) 2,2,4,4-tetramethylpentane
• d) 2,2,4,4-tetramethylhexane

Answer: 2,2,5,5-tetramethylhexane

Question: Which one of the following reactions is expected to readily give a hydrocarbon product in good yields ?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A hydrocarbon A on chlorination gives B which on heating with alcoholic potassium hydroxide changes into another hydrocarbon C. The latter decolourises Baeyer's reagent and on ozonolysis forms formaldehyde only. A is

• a) Ethane
• b) Butane
• c) Ethene
• d) Methane

Answer: Ethane

Question: Which of the following compounds can yield only one monochlorinated product upon free radical chlorination?

• a) 2, 2-Dimethylpropane
• b) n-Butane
• c) Propane
• d) 2-Methylpropane

Answer: 2, 2-Dimethylpropane

Question:

• a) the molecular plane
• b) a plane parallel to the molecular plane
• c) Both
• d) None of these

Answer: the molecular plane

Question: The IUPAC name of the compound having the formula (CH₃)₃CCH = CH₂ is –

• a) 3, 3-dimethyl-1-butene
• b) 1, 1, 1-trimethyl-1-butene
• c) 3, 3, 3-trimethyl-1-propane
• d) None of these

Answer: 3, 3-dimethyl-1-butene

Question:

• a) trans-2-chloro-3-iodo-2-pentene
• b) cis-3-iodo-4-chloro-3-pentene
• c) trans-3-iodo-4-chloro-3-pentene
• d) cis-2-chloro-3-iodo-2-pentene

Answer: trans-2-chloro-3-iodo-2-pentene

Question: The number of possible open chain (acyclic) isomeric compounds for molecular formula C₅H₁₀ would be

• a) 6
• b) 8
• c) 7
• d) 5

Answer: 6

Question: Correct order of stability is

• a) trans-2-butene > cis-2-butene > 1-butene
• b) 1-butene > cis-2-butene > trans-2- butene
• c) cis-2-butene > trans-2-butene > 1-butene
• d) cis -2- butene > 1-butene > trans -2-butene

Answer: trans-2-butene > cis-2-butene > 1-butene

Question: But-2-ene exhibits cis-trans-isomerism due to

• a) restricted rotation around C = C bond
• b) rotation around C₃ – C₄ sigma bond
• c) rotation around C₁ – C₂ bond
• d) None of these

Answer: restricted rotation around C = C bond

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Aromatisation of n-hexane gives

• a) benzene
• b) toluene
• c) cyclohexane
• d) cycloheptane

Answer: benzene

Question: When 3, 3-dimethyl 2-butanol is heated with H₂SO₄, the major product obtained is

• a) 2,3-dimethyl 2-butene
• b) 3, 3-dimethyl 1- butene
• c) 2, 3-dimethyl 1- butene
• d) cis & trans isomers of 2, 3-dimethyl 2-butene

Answer: 2,3-dimethyl 2-butene

Question:

• a) 2, 3-dimethyl-2-pentene
• b) 3, 4-dimethyl-2-pentene
• c) 3, 4-dimethyl-3-pentene
• d) 2, 3-dimethyl-3-pentene

Answer: 2, 3-dimethyl-2-pentene

Question: Reaction of hydrogen bromide with propene in the absence of peroxide is a/an

• a) electrophilic addition
• b) electrophilic substitution
• c) nucleophilic addition
• d) free radical addition

Answer: electrophilic addition

Question: Which of the following types of reaction occur when a reactant has got a double bond ?

(i) Addition
(ii) Photolysis
(iii) Nucleophilic substitution
(iv) Polymerization

• a) (i) and (iv)
• b) (iii) and (iv)
• c) (i), (ii) and (iii)
• d) (ii) and (iii)

Answer: (i) and (iv)

Question: The disappearance of the characteristic purple colour of KMnO₄ in its reaction with an alkene is the test for unsaturation. It is known as

• a) Baeyer test
• b) Grignard test
• c) Markownikoff test
• d) Wurtz test

Answer: Baeyer test

Question:  CH₂ = CHCl reacts with HCl to form

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: The only alcohol that can be prepared by the indirect hydration of alkene is

• a) Ethyl alcohol
• b) Propyl alcohol
• c) Isobutyl alcohol
• d) Methyl alcohol

Answer: Ethyl alcohol

Question: Which reactions are most common in alkenes

• a) Electrophilic addition reactions
• b) Nucleophilic addition reactions
• c) Nucleophillic substitution reactions
• d) Electrophilic substitution reactions

Answer: Electrophilic addition reactions

Question: In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti-Markownikov’s addition to alkenes because

• a) One of the steps is endothermic in both the cases
• b) All the steps are exothermic in both the cases
• c) One is oxidising and the other is reducing
• d) Both are highly ionic

Answer: One of the steps is endothermic in both the cases

Question: Which of the following statements is incorrect regarding dehydrohalogenation of alkenes ?

• a) Only nature of halogen atom determine rate of the reaction
• b) Rate of reaction for same alkyl group; Iodine > Bromine > Chlorine
• c) Both
• d) None of these

Answer: Only nature of halogen atom determine rate of the reaction

Question: How many structural isomers are possible for the alkyne C₆H₁₀ ?

• a) 7
• b) 8
• c) 6
• d) 5

Answer: 7

Question: Which of the following will have least hindered rotation around carbon - carbon bond ?

• a) Ethane
• b) Acetylene
• c) Ethylene
• d) Hexachloroethane

Answer: Ethane

Question: Acetylenic hydrogens are acidic because

• a) Sigma electron density of C – H bond in acetylene is nearer to carbon, which has 50% s-character
• b) Acetylene has only open hydrogen in each carbon
• c) Acetylene contains least number of hydrogens among the possible hydrocarbons having two carbons
• d) None of these

Answer: Sigma electron density of C – H bond in acetylene is nearer to carbon, which has 50% s-character

Question: Propyne can be prepared by dehydrohalogenation of

• a) 1, 2–dichloropropane
• b) 1, 2–dichloroethane
• c) 1, 1, 2, 2–tetrachloroethane
• d) 1–chloropropane

Answer: 1, 2–dichloropropane

Question:

• a) Ammonical silver nitrate.
• b) Bromine in acetic acid
• c) Bromine in carbon tetrachloride
• d) None of these

Answer: Ammonical silver nitrate.

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) 1 < 2 < 3
• b) 3 < 2 < 1
• c) 2 < 3 < 1
• d) 1 < 3 < 2

Answer: 1 < 2 < 3

Question:

• a)

  

• b) None of these
• c)

  

• d)

  

Answer:

Question:

• a) (i) and (iv)
• b) (i) and (iii)
• c) (ii) and (iv)
• d) (i) and (iv)

Answer: (i) and (iv)

Question: Which one of these is not compatible with arenes?

• a) Electrophilic additions
• b) Resonance
• c) Greater stability
• d) None of these

Answer: Electrophilic additions

Question:

• a) Functional isomer
• b) Position isomer
• c) Chain isomer
• d) Stereoisomer

Answer: Functional isomer

Question: The carbon-carbon bond length in benzene is

• a) In between C₂H₆ and C₂H₄
• b) In between C₂H₄ and C₂H₂
• c) Same as in C₂H₄
• d) None of these

Answer: In between C₂H₆ and C₂H₄

Question: Point out the wrong statement in relation to the structure of benzene

• a) It forms only one monosubstitution product
• b) The C - C bond distance in benzene is uniformly 1.397Å
• c) It is a resonance hybrid of a number of canonical forms
• d) None of these

Answer: It forms only one monosubstitution product

Question:

• a) 4
• b) 2
• c) 3
• d) 8

Answer: 4

Question:

• a) 6 p-orbitals and 6 unpaired electrons
• b) 6 p-orbitals and 7 unpaired electrons
• c) 7 p-orbitals and 7 unpaired electrons
• d) 7 p-orbitals and 6 unpaired electrons

Answer:  6 p-orbitals and 6 unpaired electrons

Question: (i) Chlorobenzene and (ii) benzene hexachloride are obtained from benzene by the reaction of chlorine, in the pesence of

• a) (i) Direct sunlight and (ii) anhydrous AlCl₃
• b) (i) Sodium hydroxide and (ii) sulphuric acid
• c) (i) Ultraviolet light and (ii) anhydrous FeCl₃
• d) (i) Anhydrous AlCl₃ and (ii) direct sunlight

Answer: (i) Direct sunlight and (ii) anhydrous AlCl₃

Question: A group which deactivates the benzene ring towards electrophilic substitution but which directs the incoming group principally to the o- and p-positions is

• a) –Cl
• b) –C₂H₅
• c) –NH₂
• d) –NO₂

Answer:  –Cl

Question: Benzene can be obtained by heating either benzoic acid with X or phenol with Y. X and Y are respectively.

• a) Soda lime and zinc dust
• b) Zinc dust and soda lime
• c) Zinc dust and sodium hydroxide
• d) Soda lime and copper

Answer: Soda lime and zinc dust

Question:  Which of the following chemical system is non aromatic?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Which of the following statements is false for isopentane

• a) It has a carbon which is not bonded to hydrogen
• b) It has one CH group
• c) It has one CH₂ group
• d) None of these

Answer: It has a carbon which is not bonded to hydrogen