NEET Chemistry Organic Chemistry Some Basic Principles and Techniques MCQs Set B

Question:  Given :

The enthalpy of hydrogenation of these compounds will be in the order as 

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

Answer: III > II > I

Question: In Duma's method for estimation of nitrogen, 0.25 g of an organic compound gave 40 mL of nitrogen collected at 300 K temperature and 725 mm pressure. If the aqueous tension at 300 K is 25 mm, the percentage of nitrogen in the compound is

• a) 15.76
• b) 17.36
• c) 18.20
• d) 16.76

Answer: 16.76

Question:  Given

Which of the given compounds can exhibit tautomerism? 

• a) I, II and III
• b) I and II
• c) I and III
• d) II and III

Answer: I, II and III

Question:  In the Kjeldahl's method for estimation of nitrogen present in a soil sample, ammonia evolved from 0.75 g of sample neutralized 10 mL of 1 M H₂SO₄. The percentage of nitrogen in the soil is 

• a) 37.33
• b) 45.33
• c) 35.33
• d) 43.33

Answer: 37.33

Question: The structure of isobutyl group in an organic compound is

• a)

  

• b) CH₃–CH₂–CH₂–CH₂–
• c)

  

• d)

  

Answer:

Question:  The radical,

is aromatic because it has 

• a) 7 p-orbitals and 6 unpaired electrons
• b) 7 p-orbitals and 7 unpaired electrons
• c) 6 p-orbitals and 7 unpaired electrons
• d) 6 p-orbitals and 1 unpaired electron

Answer: 6 p-orbitals and 1 unpaired electron

Question:  The order of stability of the following tautomeric compounds is

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

Answer: III > II > I

Question: Structure of the compound whose IUPAC name is 3-ethyl-2-hydroxy-4-methylhex-3-en-5-ynoic acid is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Some meta-directing substituents in aromatic substitution are given. Which one is most deactivating?

• a) –SO₃H 
• b) –COOH
• c) –NO₂  
• d) –C≡N

Answer: –NO₂  

Question: Which of the following compounds will not undergo Friedal-Craft's reaction easily?

• a) Xylene
• b) Nitrobenzene
• c) Toluene
• d) Cumene

Answer: Nitrobenzene

Question: Among the following compounds the one that is most reactive towards electrophilic nitration is

• a) Toluene
• b) Benzene
• c) Benzoic acid
• d) Nitrobenzene

Answer: Toluene

Question: In Dumas' method of estimation of nitrogen 0.35 g of an organic compound gave 55 mL of nitrogen collected at 300 K temperature and 715 mm pressure. The percentage composition of nitrogen in the compound would be: (Aqueous tension at 300 K = 15 mm)

• a) 14.45
• b) 15.45
• c) 16.45
• d) 17.45

Answer: 16.45

Question: Considering the state of hybridization of carbon atoms, find out the molecule among the following which is linear?

• a) CH₃– CH₂– CH₂– CH₃ 
• b) CH₃– CH = CH – CH₃
• c) CH₃– C ≡ C – CH₃  
• d) CH₂= CH – CH₂– C ≡  CH

Answer: CH₃– C ≡ C – CH₃  

Question: The Lassaigne's extract is boiled with conc. HNO₃ while testing for halogens. By doing so it 

• a) Increases the concentration of NO₃^– ions  
• b) Decomposes Na₂S and NaCN, if formed
• c) Helps in the precipitation of AgCl
• d) Increases the solubility product of AgCl

Answer:  Decomposes Na₂S and NaCN, if formed

Question:  The correct IUPAC name of the compound

• a) 3-(1-ethyl propyl) hex-1-ene
• b) 4-Ethyl-3-propyl hex-1-ene
• c) 3-Ethyl-4-ethenyl heptane
• d) 3-Ethyl-4-propyl hex-5-ene

Answer: 4-Ethyl-3-propyl hex-1-ene

Question: Which one of the following is most reactive towards electrophillic reagent?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  The IUPAC name of the following compound is

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

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

Question: Which of the following species is not electrophilic in nature ?

• a)

  

• b) BH₃
• c)

  

• d)

  

Answer:

Question:  The IUPAC name of the compound CH₃CH =CHC ≡ CH is 

• a) Pent-4-yn-2-ene
• b) Pent-3-en-1-yne
• c) Pent-2-en-4-yne
• d) Pent-1-yn-3-ene

Answer: Pent-3-en-1-yne

Question:  The state of hybridization of C₂, C₃, C₅ and C₆ of the hydrocarbon,

is in the following  sequence 

• a) sp³, sp², sp² and sp 
• b) sp, sp², sp² and sp³
• c) sp, sp², sp³ and sp² 
• d) sp, sp³, sp² and sp³

Answer:  sp, sp³, sp² and sp³

Question:  The IUPAC name of the compound having the formula 

  is 

• a) 1-butyn-3-ene
• b) but-1-yne-3-ene
• c) 1-butene-3-yne
• d) 3-butene-1-yne

Answer: 1-butene-3-yne

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

Question: Which of the following compounds will exhibit cis-trans (geometrical) isomerism?

• a) Butanol
• b) 2-Butyne
• c) 2-Butenol
• d) 2-Butene

Answer: 2-Butene

Question:  In the hydrocarbon  

The state of hybridization of carbons 1,3 and 5 are in the following sequence 

• a) sp³, sp², sp 
• b) sp², sp, sp³
• c) sp, sp³, sp² 
• d) sp, sp², sp³

Answer: sp, sp³, sp² 

Question:  The stability of carbanions in the following

is in the order of 

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

Answer: a > b > c > d

Question:  Base strength of

is in the order of 

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

Answer: a > b > c

Question: Which one of the following is most reactive towards electrophilic attack?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The general molecular formula, which represents the homologous series of alkanols is

• a) C_nH_2nO₂ 
• b) C_nH_2nO
• c) C_nH_2n+1O
• d) C_nH_2n+2O

Answer:  C_nH_2n+2O

Question:  The IUPAC name of

• a) 3, 4-dimethylpentanoyl chloride
• b) 1-chloro-1-oxo-2, 3-dimethylpentane
• c) 2-ethyl-3-methylbutanoyl chloride
• d) 2, 3-dimethylpentanoyl chloride

Answer: 2, 3-dimethylpentanoyl chloride

Question: Which amongst the following is the most stable carbocation?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which one of the following pairs represents stereoisomerism?

• a) Chain isomerism and rotational isomerism
• b) Structural isomerism and geometric isomersm
• c) Linkage isomerism and geometric isomerism
• d) Optical isomerism and geometric isomerism

Answer: Optical isomerism and geometric isomerism

Question: The substance which can be used as an adsorbent in column chromatography is

• a) Na₂O 
• b) NaCl
• c) Al₂O₃
• d) Alum

Answer:  Al₂O₃

Question:  In the estimation of Duma's method 1.18g of an organic compound gave 224 ml of N₂(g) at NTP. The percentage of N in the compound is about

• a) 20.0
• b) 11.8
• c) 47.5
• d) 23.7

Answer: 23.7

Question:  0.5 g of an organic compound cantaining N on kjeldahlising required 29 ml of N/5 H₂SO₄ for complete neutralization of NH₃. The percentage of N in the compound is

• a) 34.3
• b) 16.2
• c) 21.6
• d) 14.8

Answer: 16.2

Question: 0.4 g of Organic Compound gave 0.188g of AgBr. The percentage of Br in the compound is

• a) 39.8
• b) 46.0
• c) 20.0
• d) 40.0

Answer: 20.0

Question: F cannot be tested by "Lassaigne's test" because

• a) F is highly reactive
• b) AgF is soluble in H₂O
• c) F is more electronegative
• d) F– shows high lattice energy

Answer:  AgF is soluble in H₂O

Question:  0.20 g of organic compound gave 0.5544 g of BaSO₄. The percentage of S is

• a) 38%
• b) 19%
• c) 18%
• d) 83%

Answer: 38%

Question:  0.64 g of organic compound give 1.2535 g of Mg₂P₂O₇. The percentage of P is

• a) 53.86%
• b) 35.86%
• c) 50%
• d) 60%

Answer: 53.86%

Question: Which of the following will not give the Lassaigne test for nitrogen?

• a) NH₂–NH₂  
• b) C₆H₅– N = N – C₆H₅
• c) CH₃CONH₂
• d) CH₃CN

Answer: NH₂–NH₂  

Question:  In detection of 'P' by fusing with Na₂O₂ and then extracting it with water, we add HNO₃(conc.) and ammonium molybdate to get

• a) Yellow ppt of (NH₃)₃PO₄   
• b) Yellow ppt of (NH₄)₃PO₄.12MoO₃
• c) White ppt of (NH₄)₃PO₄  
• d) White ppt. of (NH₄)₂HPO₃

Answer: Yellow ppt of (NH₄)₃PO₄.12MoO₃

Question: Which is not correct match?

• a) Carius method – Halogens
• b) Leibig’s method – C and hydrogen
• c) Kjeldahl’s method – N₂
• d) Lassaigne’s test – O₂

Answer: Lassaigne’s test – O₂

Question:  Which of the following should be a sp³ hybridised free radical?

• a)

  

• b)

  

• c)

  

• d) Both (2) & (3)

Answer: Both (2) & (3)

Question:

Above two molecules are

• a) Chain isomers
• b) Position isomers
• c) Metamers
• d) All of these

Answer: Chain isomers

Question: Aromatic enol is not possible in

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The correct order of +I effect is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The charge on given atom cannot be dispersed on other atom in

• a)

  

• b)

  

• c)

  

• d) All of these

Answer:

Question:  The correct order of stability of given carbocations is

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

Answer: IV > I > II > III

Question:  The correct order of stability of given corbocations is

• a) VII > III > II > IV > V > I > VI
• b) V > III > IV > II > VI > I > VII
• c) V > IV > III > II > VII > I > VI
• d) VI > I > VII > III > II > V > IV

Answer: V > IV > III > II > VII > I > VI

Question: The stability of alkyl free radicals is due to

• a) Hyperconjugation
• b) + I effect
• c) – I effect
• d) Both (2) & (3)

Answer: Both (2) & (3)

Question:  In the given compound

The correct order of reactivity of H atoms towards free radical substitution is

• a) 2 > 4 > 6 > 5 > 3 > 1
• b) 2 > 4 > 5 > 6 > 1 > 3
• c) 1 > 4 > 2 > 5 > 6 > 3
• d) 3 > 1 > 5 > 6 > 4 > 2

Answer: 2 > 4 > 5 > 6 > 1 > 3

Question:  Which of the following is the correct order of reactivity of chlorides for given compounds?

• a) I > II > III > IV > V
• b) I > III > II > IV > V
• c) III > I > IV > V > II
• d) I > III > IV > V > II

Answer: I > III > IV > V > II

Question:  In the given reaction

A and B are respectively

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

 Intermediate (Major)

The most stable carbocation is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  In which of the following rearranged 3° carbocation will not be formed?

• a)

  

• b)

  

• c)

  

• d) Both (1) & (3)

Answer: Both (1) & (3)

Question: The least reactive alkene towards dil. HCl is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The most stable carbocation is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: 2,3-Dimethyl-2-butene can be prepared by heating which of the following compounds with a strong acid?

• a) (CH₃)₂C = CH – CH₂– CH₃
• b) (CH₃)₂CH – CH₂– CH = CH₂
• c)

  

• d) (CH₃)₃C – CH = CH₂

Answer:  (CH₃)₃C – CH = CH₂

Question:  The number of structural isomers possible from the molecular formula C₃H₉N is 

• a) 2
• b) 3
• c) 4
• d) 5

Answer: 4

Question: Which of the following statements is not correct for a nucleophile?

• a) Nucleophiles attack low e^– density sites
• b) Nucleophiles are not electron seeking
• c) Nucleophile is a Lewis acid
• d) Ammonia is a nucleophile

Answer: Nucleophile is a Lewis acid

Question:  Consider the following compounds

Hyperconjugation occurs in 

• a) I and III
• b) I only
• c) II only
• d) III only

Answer: III only

Question: Which of the following is the most correct electron displacement for a nucleophilic reaction to take place?

• a)

  

• b)

  

• c)

  

• d)

  

Answer: