NEET Chemistry Hydrocarbons MCQs Set A

Question: The difference in potential energy between eclipsed and staggered form of ethane is

• a) 4 kJ/mol
• b) 12.55 kJ/mol
• c) 2 kJ/mol
• d) 44 kJ/mol

Answer: 12.55 kJ/mol

Question: Eclipsed form of ethane has higher energy due to

• a) Torsional strain
• b) Steric strain
• c) Angle strain
• d) Both (1) & (2)

Answer: Both (1) & (2)

Question: The angle strain in cyclopentane is

• a) 72°
• b) 1°28’ 
• c) 44’ 
• d) 108°

Answer: 44’ 

Question: Which one is most stable?

• a) Cyclopropane
• b) Cyclobutane
• c) Cyclopentane
• d) Cyclohexane

Answer: Cyclohexane

Question: The chair form is _______ stable than boat form by potential energy _______ kJ/mol.

• a) More, 44 kJ/mol
• b) Less, 44 kJ/mol
• c) More, 12.55 kJ/mol
• d) Less, 4 kJ/mol

Answer: More, 44 kJ/mol

Question: Which one is not aromatic compound?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which one of the following statement is not correct for sigma- and pi-bonds formed between two carbon atoms?

• a) Sigma-bond is stronger than a pi-bond
• b) Bond energies of sigma- and pi-bonds are of the order of 264 kJ/mol and 347 kJ/mol, respectively
• c) Free rotation of atoms about a sigma-bond is allowed but not in case of a pi-bond
• d) Sigma-bond determines the direction between carbon atoms but a pi-bond has no primary effect in this regard

Answer: Bond energies of sigma- and pi-bonds are of the order of 264 kJ/mol and 347 kJ/mol, respectively

Question:

• a)

  

• b)

  

• c)

  

• d) Both (2) & (3)

Answer: Both (2) & (3)

Question: On electrolysis of sodium succinate, the alkene obtained is ______ and nature of solution after electrolysis is ______.

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which one is not prepared by Wurtz reaction?

• a) C₂H₆
• b) n-C₄H₁₀
• c) CH₄
• d)

  

Answer:  CH₄

Question:

can be prepared by

• a) Wurtz reaction
• b) Fittig reaction
• c) Wurtz Fittig reaction
• d) Frankland reaction

Answer: Wurtz Fittig reaction

Question:

The incorrect statement for C is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  In the following compounds the decreasing order of B.P. is

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

Answer: (I) > (II) > (III)

Question:

The compound "A" is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Benzene
• b) Duetero benzene
• c) Duetero toluene
• d) Both (2) & (3)

Answer: Duetero benzene

Question: In iodination ; for preparation of iodomethane compound used is

• a) HIO₃
• b) HgO
• c) Both (1) & (2)
• d) HI

Answer: Both (1) & (2)

Question:  In chlorination the relation rate of abstraction of H in 3°, 2° and 1°C atom respectively

• a) 5 : 3.8 : 2
• b) 5 : 3.8 : 1
• c) 1600 : 82 : 1
• d) 1600 : 5 : 82

Answer: 5 : 3.8 : 1

Question: In which alkane isomerization will not occur?

• a) C₂H₆ 
• b) C₄H₁₀
• c) C₅H₁₀ 
• d) C₆H₁₄

Answer:  C₂H₆ 

Question:

compound "A" is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

The minimum heat of hydrogenation is in

• a)

  

• b)

  

• c) Both have equal
• d) Cannot predict

Answer:

Question:

• b)

  

• c)

  

• d)

  

Answer:

Question: In which of the following reactions Markovnikov’s rule is not observed ?

• a)

  

• b)

  

• c)

  

• d) Both (2) & (3)

Answer: Both (2) & (3)

Question:  The reaction of CH₃CH = CH₂ with HOCl will yield

• a) 2-chloro-1-propanol
• b) 3-chloro-2-propanol
• c) 1-chloro-2-propanol
• d) 1-chloro-1-propanol

Answer: 1-chloro-2-propanol

Question:  What is X in the following sequence of reactions?

• a) Methane
• b) Ethanoic acid
• c) Propane
• d) None of these

Answer: Ethanoic acid

Question: Addition of HBr to propene

• a) Follows Markovnikov’s rule
• b) Does not follow Markovnikov’s rule
• c) Follows Markovnikov’s rule but the product rearranges to give anti–Markovnikov’s product
• d) Follows free radical mechanism

Answer: Follows Markovnikov’s rule

Question: In an attempt to prepare propane by Wurtz reaction 1 mole of methyl bromide and 1 mole of ethyl bromide are treated with sodium. Assuming equal probability for all possible reaction. How many g of propane will be obtained?

• a) 44 g
• b) 22 g
• c) 33 g
• d) 14.67 g

Answer: 14.67 g

Question: Addition of HBr to 2-methyl-1-propene in the presence of hydrogen-peroxide produces

• a) 1-Bromobutane
• b) 2-Bromopropane
• c) 2-Bromo-2-methylpropane
• d) 1-Bromo-2-methylpropane

Answer: 2-Bromo-2-methylpropane

Question:  Toluene

Here Y is

• a) Benzaldehyde
• b) Toluene
• c) Benzoic acid
• d) Ethylbenzene

Answer: Benzoic acid

Question:  C₆H₅CH₂CH₂CH₃ is when oxidised in the presence of alk. KMnO₄, the product obtained is

• a) C₆H₅CHO
• b) C₆H₅COOH
• c) C₆H₅CH₂CH₂CHO 
• d) C₆H₅COCH₃

Answer:  C₆H₅COOH

Question:

Z is

• a) Acetic acid
• b) Acetic anhydride
• c) Acetone
• d) Chloromethane

Answer: Chloromethane

Question:

Here, X is

• a) Maleic anhydride
• b) Acetic acid
• c) Propanoic acid
• d) Succinic acid

Answer: Maleic anhydride

Question: In Kharasch effect; reaction follows

• a) Free radical substitution
• b) Electrophilic addition
• c) Free radical addition
• d) Nucleophilic addition

Answer: Free radical addition

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

is

• a) CH₃– CH = CH – CH₃ 
• b) CH₂= CH – CH₂– CH₃
• c)

  

• d) Both (2) & (3)

Answer:  CH₂= CH – CH₂– CH₃

Question:

• a) C₂H₆ 
• b) CH₄
• c) CH₃COOH
• d) CH₃COONa

Answer:  CH₄

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b) CH₂O
• c)

  

• d) CH₃CHO

Answer:  CH₃CHO

Question:

• a)

  

• b)

  

• c)

  

• d) All of these

Answer: All of these

Question: Baeyer’s reagent is

• a) 1% Alkaline KMnO₄
• b) Acidic KMnO₄
• c) Neutral KMnO₄  
• d) Aq. Br₂ solution

Answer: 1% Alkaline KMnO₄

Question: Acetylene when oxidized with chromic acid gives

• a) Ethylene glycol
• b) Oxalic acid
• c) Formic acid
• d) Acetic acid

Answer: Acetic acid

Question: The catalyst used to reduce an alkyne to alkene is

• a) Raney Nickel
• b) Palladium
• c) Lindlar’s catalyst
• d) Iron

Answer: Lindlar’s catalyst

Question: Benzene undergoes substitution reaction more easily than addition because

• a) It has a cyclic structure
• b) It has three double bonds
• c) Of delocalization of π-electrons
• d) It has six hydrogen atoms

Answer:  Of delocalization of π-electrons

Question:  A mixture of C₂H₆, C₂H₄ and C₂H₂ is bubbled through alkaline solution of copper (I) chloride, contained in Woulf’s bottle.The gas coming out is

• a) Original mixture
• b) C₂H₆
• c) C₂H₆ and C₂H₄mixture 
• d) C₂H₄ and C₂H₂

Answer:  C₂H₆ and C₂H₄mixture 

Question:  Ethylene + S₂Cl₂—→ "A" ; The compound "A" is

• a) Lewisite
• b) Mustard oil
• c) Mustard gas
• d) Insecticide

Answer: Mustard gas

Question:

Addition of H₂O in the reaction is an example of

• a) Electrophilic addition
• b) Nucleophilic addition
• c) Free radical addition
• d) Electrophilic substitution

Answer: Nucleophilic addition

Question: Monomer of neoprene is

• a) Chloroprene
• b) Acetylene
• c) Vinyl acetylene
• d) Both (2) & (3)

Answer: Acetylene

Question:

Compound "A" is

• a) H₃PO₂

   

• b) H₃PO₃
• c) H₃PO₄ 
• d) Both (1) & (2)

Answer: Both (1) & (2)

Question:

Compound "A" is

• a) Isopropyl benzene
• b) Cumene
• c) An alkyl derivative of benzene
• d) All of these

Answer: All of these

Question: In sulphonation of benzene; electrophilic reagent used is

• a)

  

• b) SO₃
• c)

  

• d)

  

Answer:  SO₃

Question: Which one is o, p-directing group for electrophilic substitution reaction?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

The decreasing order of reactivity towards electrophilic substitution reaction is

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

Answer: (I) > (III) > (II)

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The electrophile which attacks in Friedel-Craft acylation is

• a)

  

• b)

  

• c)

  

• d) Both (1) & (3)

Answer:

Question: Which of the following shows geometrical isomerism?

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

Answer: But-2-ene

Question:

The best suitable reagent 'A' is

• a) C₃H₈S₂/H₂/Ni 
• b) N₂H₄/KOH 
• c) Zn–Hg/conc. HCl
• d) HI/P(red)

Answer:  N₂H₄/KOH 

Question:

The most suitable reagent for given conversion is

• a) Diimide
• b) H₂/Ni₂B
• c) Zn/dil. HCl
• d) LiAlH₄

Answer: Diimide

Question:  Consider the following two structures

Choose the correct statement

• a) Both (i) & (ii) are conjugated system
• b) (i) & (ii) both show resonance
• c) (i) & (ii) both are aromatic
• d) (i) is less stable than (ii)

Answer: Both (i) & (ii) are conjugated system

Question:

In above reaction product (B) is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  In the given reaction

The product will be

• a)

  

• b)

  

• c)

  

• d) Mixture of (1) & (2)

Answer:

Question:

Product (C) is

• a) Mixture of n-butane, ethane
• b) Only propane
• c) Only ethane
• d) n-hexane

Answer: Only propane