NEET Chemistry Hydrocarbons MCQs Set B

Question:  Natural rubber is a polymer of isoprene (2-methyl buta-1, 3-diene). If natural rubber is treated with O₃ followed by Zn/H₂O, the final product will be

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

Product (C) is

• a) Propanal
• b) Butanal
• c) 2-pentanone
• d) Propanone

Answer: Propanone

Question:  In the given reaction

The number of moles of HI required for conversion is

• a) 12
• b) 8
• c) 14
• d) 10

Answer: 12

Question:  Dehydration by conc. H₂SO₄ is the most difficult in

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following can form methane gas with methyl magnesium bromide?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

A & B are respectively

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following compound is paramagnetic?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

In above reaction product (C) is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  In which of the following dehydration by conc. H₂SO₄ no rearrangement is favourable?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: In the reaction with HCl, an alkene reacts in accordance with the Markovnikov's rule, to give a product 1-chloro-1-methylcyclohexane. The possible alkene is

• a)

  

• b)

  

• c) (A) and (B)
• d)

  

Answer: (A) and (B)

Question:  A single compound of the structure

is obtainable from ozonolysis of which of the following cyclic compounds?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  The reaction of C₆H₅CH = CHCH₃ with HBr produces

• a)

  

• b)

  

• c)

  

• d) C₆H₅CH₂CH₂CH₂Br

Answer:

Question:  Which of the following organic compounds has same hybridization as its combustion product-(CO₂) ?

• a) Ethane
• b) Ethyne
• c) Ethene
• d) Ethanol

Answer: Ethyne

Question: Which of the following reagents will be able to distinguish between 1-butyne and 2-butyne ?

• a) NaNH₂  
• b) HCl
• c) O₂
• d) Br₂

Answer: NaNH₂  

Question: Liquid hydrocarbons can be converted to a mixture of gaseous hydrocarbons by

• a) Oxidation
• b) Cracking
• c) Distillation under reduced pressure
• d) Hydrolysis

Answer: Cracking

Question:  The reaction of toluene with Cl₂ in presence of FeCl₃ gives 'X' and reaction in presence of light gives 'Y'. Thus, 'X' and 'Y' are 

• a) X = Benzal chloride, Y = o-chlorotoluene
• b) X = m-chlorotoluene, Y = p-chlorotoluene
• c) X = o-and p-chlorotoluene, Y = Trichloromethyl benzene
• d) X = Benzyl chloride, Y = m-chlorotoluene

Answer:  X = o-and p-chlorotoluene, Y = Trichloromethyl benzene

Question: In the following the most stable conformation of n-butane is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  Benzene reacts with CH₃Cl in the presence of anhydrous AlCl₃ to form 

• a) Chlorobenzene
• b) Benzylchloride
• c) Xylene
• d) Toluene

Answer: Toluene

Question:  Nitrobenzene can be prepared from benzene by using a mixture of conc. HNO₃ and conc. H₂SO₄ in the mixture,nitric acid acts as a/an 

• a) Acid
• b) Base
• c) Catalyst
• d) Reducing agent

Answer: Base

Question:  How many stereoisomers does the molecules have? CH₃CH = CHCH₂CHBrCH₃

• a) 2
• b) 4
• c) 6
• d) 8

Answer: 4

Question: The order of decreasing reactivity towards an electrophilic reagent, for the following would be a. Benzene b. Toluene c. Chlorobenzene d. Phenol

• a) d > b > a > c
• b) a > b > c > d
• c) b > d > a > c
• d) d > c > b > a

Answer: d > b > a > c

Question:  Predict the product C obtained in the following reaction

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  Which one of the following alkenes will react faster with H₂ under catalytic hydrogenation conditions ?

• a)

  

  (R = Alkyl substituent)

• b)

  

• c)

  

• d)

  

Answer:

(R = Alkyl substituent)

Question: Which is maximum stable?

• a) But-1-ene
• b) cis-but-2-ene
• c) trans-but-2-ene
• d) All have equal

Answer: trans-but-2-ene

Question: Geometrical isomers differ in

• a) Position of functional group
• b) Position of atoms
• c) Spatial arrangement of atoms
• d) Length of carbon chain

Answer: Spatial arrangement of atoms

Question: The correct order of reactivity towards the electrophilic substitution of the compounds aniline (I), benzene (II)and nitrobenzene (III) is

• a) III > II > I
• b) II > III I
• c) I < II > III
• d) I > II > III

Answer: I > II > III

Question: The reactive species in the nitration of benzene is

• a) NO₃  
• b) NHO₃
• c) NO₂⁺
• d) NO₂^–

Answer:  NO₂⁺

Question:

A (predominantly) is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  The alkene R–CH = CH₂ reacts readily with B₂H₆ and the product on oxidation with alkaline hydrogen peroxides produces

• a)

  

• b)

  

• c) R–CH₂–CHO
• d) R–CH₂–CH₂–OH

Answer:  R–CH₂–CH₂–OH

Question:  Electrophile in the case of chlorination of benzene in the presence of FeCl₃ is

• a) Cl
• b) FeCl₃
• c) Cl⁺
• d) Cl^–

Answer:  Cl⁺

Question: The bond length between central carbon atom and other carbon atom is minimum in

• a) Propene
• b) Propyne
• c) Propane
• d) Pentane

Answer: Propyne

Question: Which of the following is used as an anti-knocking material?

• a) Glyoxal
• b) Freon
• c) T.E.L.
• d) Ethyl alcohol

Answer: T.E.L.

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

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  In a reaction : 

where M = Molecule and R = Reagent. M and R are

• a) CH₃CH₂OH and HCl   
• b) CH₃–CH₃ and heat
• c) CH₃CH₂Cl and NaOH
• d) CH₂Cl–CH₂OH and aq. NaHCO₃

Answer:  CH₂Cl–CH₂OH and aq. NaHCO₃

Question: The cylindrical shape of alkyne is due to

• a) Two sigma C–C and one π C–C bonds 
• b) One sigma C–C and two  π C–C bonds
• c) Three sigma C–C bonds
• d) Three  π C–C bonds

Answer: One sigma C–C and two  π C–C bonds

Question: In the commercial gasolines, the type of hydrocarbons which are more desirable is

• a) Linear unsaturated hydrocarbon
• b) Toluene
• c) Branched hydrocarbon
• d) Straight-chain hydrocarbon

Answer: Branched hydrocarbon

Question: The most stable conformation of n-butane is

• a) Gauche
• b) Staggered
• c) Skew boat
• d) Eclipsed

Answer: Staggered

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

• a) Electrophilic additions
• b) Delocalisation of π-electrons
• c) Greater stability
• d) Resonance

Answer: Electrophilic additions

Question:  When acetylene is passed through dil. H₂SO₄ in the presence of HgSO₄ , the compound formed is

• a) Acetic acid
• b) Ketone
• c) Ether
• d) Acetaldehyde

Answer: Acetaldehyde

Question:  In Friedel-Craft’s alkylation, besides AlCl₃ the other reactants are

• a) C₆H₆+ CH₃Cl  
• b) C₆H₆+ CH₄  
• c) C₆H₆+ NH₂– NH₂
• d) C₆H₆+ CH₃COCl

Answer:  C₆H₆+ CH₃Cl  

Question: Gammexane is

• a) Bromobenzene
• b) Benzyl Chloride
• c) Chlorobenzene
• d) Benzene hexachloride

Answer: Benzene hexachloride

Question: In Friedel-Crafts reaction, toluene can be prepared by

• a) C₆H₆+ CH₃Cl  
• b) C₆H₅Cl + CH₄
• c) C₆H₆+ CH₂Cl₂  
• d) C₆H₆+ CH₃COCl

Answer:  C₆H₆+ CH₃Cl  

Question: 2-butene shows geometrical isomerism due to

• a) Restricted rotation about double bond
• b) Free rotation about double bond
• c) Free rotation about single bond
• d) Chiral carbon

Answer: Restricted rotation about double bond

Question: Dihedral angle in staggered form of ethane is

• a) 0° 
• b) 120°
• c) 60° 
• d) 180°

Answer: 60° 

Question: Which alkene on ozonolysis gives 

• a)

  

• b) CH₃CH₂CH = CHCH₂CH₃
• c) CH₃CH₂CH = CHCH₃
• d)

  

Answer:

Question: In preparation of alkene from alcohol using Al₂O₃ which is the effective factor?

• a) Porosity of Al₂O₃
• b) Temperature
• c) Concentration
• d) Surface area of Al₂O₃

Answer: Temperature

Question: The compound

on reaction with NaIO₄ in the presence of KMnO₄ gives

• a) CH₃COCH₃ 
• b) CH₃COCH₃+ CH₃COOH 
• c) CH₃COCH₃+ CH₃CHO
• d) CH₃CHO + CO₂

Answer: CH₃COCH₃+ CH₃COOH 

Question:   Products of the following reaction       

are

• a)

  

• b) CH₃COOH + HOOC.CH₂CH₃
• c) CH₃CHO + CH₃CH₂CHO 
• d) CH₃COOH + CH₃COCH₃

Answer:

Question:  Which of the compounds with molecular formula C₅H₁₀ yields acetone on ozonolysis?

• a) 3-methylbut-1-ene
• b) Cyclopentane
• c) 2-methylbut-1-ene
• d) 2-methylbut-2-ene

Answer: 2-methylbut-2-ene

Question: One of the following which does not observe the anti-Markownikoff’s addition of HBr, is

• a) Pent-2-ene
• b) Propene
• c) But-2-ene
• d) But-1-ene

Answer: But-2-ene

Question:  Given

I and II are

• a) A pair of optical isomers
• b) Identical
• c) A pair of conformers
• d) A pair of geometrical isomers

Answer: A pair of conformers

Question: Reaction of HBr with propene in the presence of peroxide gives

• a) Isopropyl bromide
• b) 3-bromo propane
• c) Allyl bromide
• d) n-propyl bromide

Answer: n-propyl bromide

Question: Which of the following conformers for ethylene glycol is most stable?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which one of the following is a free-radical substitution reaction?

• a)

  

• b)

  

• c)

  

• d)

  CH₃CHO + HCN → CH₃CH(OH)CN

Answer:

Question:  Using anhydrous AlCl₃ as catalyst, which one of the following reactions produces ethylbenzene (PhEt)?

• a) H₃C – CH₂OH + C₆H₆  
• b) CH₃– CH = CH₂+ C₆H₆
• c) H₂C = CH₂+ C₆H₆  
• d) H₃C – CH₃+ C₆H₆

Answer: H₂C = CH₂+ C₆H₆  

Question: Which of the following compounds undergoes nucleophilic substitution reaction most easily?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  Consider the reactions :

The mechanisms of reactions (i) and (ii) are respectively

• a) S_N2 and S_N2 
• b) S_N2 and S_N1
• c) S_N1 and S_N2 
• d) S_N1 and S_N1

Answer: S_N2 and S_N2 

Question:  Which will undergo fastest S_N2 substitution reaction when treated with NaOH?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Monobromination of 2-methylbutane gives how many distinct isomers?

• a) One
• b) Two
• c) Three
• d) Four

Answer: Four

Question:  Given reaction 

(main product) Y in the reaction is

• a) Hexane
• b) Cyclohexane
• c) Cyclohexylcyclohexane
• d) Cyclohexylether

Answer: Cyclohexane