LUMS LCAT Chemistry Organic Chemistry — Set 3

LUMS LCAT Chemistry Organic Chemistry — Set 3

1. Question 1

   Q1. The functional group in CH3CONH2 is?

   • A) Amide
   • B) Amine
   • C) Nitrile
   • D) Ester

   Answer: Amide

   Explanation: CH3CONH2 contains the amide functional group (-CONH2).

2. Question 2

   Q2. The reaction between an aldehyde and Tollens' reagent gives?

   • A) Carboxylic acid
   • B) Alcohol
   • C) Silver mirror
   • D) Ketone

   Answer: Silver mirror

   Explanation: Tollens' reagent oxidizes aldehydes to carboxylates, producing a silver mirror.

3. Question 3

   Q3. The most stable conformation of butane is?

   • A) Eclipsed
   • B) Staggered
   • C) Gauche
   • D) Anti

   Answer: Anti

   Explanation: The anti-conformation is the most stable due to minimum steric hindrance.

4. Question 4

   Q4. The compound that does not react with Na is?

   • A) CH3CH2OH
   • B) C6H5OH
   • C) CH3COOH
   • D) C6H5NH2

   Answer: C6H5NH2

   Explanation: C6H5NH2 (aniline) does not react with Na because it is a weaker acid than alcohols and carboxylic acids.

5. Question 5

   Q5. What is the product of the reaction of benzene with CH3Cl/AlCl3?

   • A) Toluene
   • B) Chlorobenzene
   • C) Benzaldehyde
   • D) Benzyl chloride

   Answer: Toluene

   Explanation: Friedel-Crafts alkylation of benzene with CH3Cl/AlCl3 gives toluene.

6. Question 6

   Q6. The strongest acid among the following is?

   • A) HCOOH
   • B) CH3COOH
   • C) C6H5COOH
   • D) ClCH2COOH

   Answer: ClCH2COOH

   Explanation: ClCH2COOH is the strongest acid due to the electron-withdrawing effect of Cl, stabilizing the conjugate base.

7. Question 7

   Q7. The reaction of an alkene with KMnO4 is an example of?

   • A) Oxidative cleavage
   • B) Electrophilic addition
   • C) Nucleophilic substitution
   • D) Electrophilic substitution

   Answer: Oxidative cleavage

   Explanation: KMnO4 oxidatively cleaves alkenes, breaking the double bond.

8. Question 8

   Q8. The compound with the formula C4H9Cl has how many isomers?

   • A) 2
   • B) 4
   • C) 6
   • D) 8

   Answer: 4

   Explanation: C4H9Cl has 4 structural isomers based on different arrangements of the Cl atom and the butane chain.

9. Question 9

   Q9. The reaction of a Grignard reagent with a ketone gives?

   • A) Tertiary alcohol
   • B) Secondary alcohol
   • C) Primary alcohol
   • D) Aldehyde

   Answer: Tertiary alcohol

   Explanation: Grignard reagent adds to ketones to form tertiary alcohols after acidification.

10. Question 10

    Q10. Which of the following is an example of a heterocyclic compound?

    • A) Benzene
    • B) Pyridine
    • C) Cyclohexane
    • D) Hexane

    Answer: Pyridine

    Explanation: Heterocyclic compounds contain at least one atom other than carbon in the ring. Pyridine has a nitrogen atom.

11. Question 11

    Q11. The hybridization of carbon in methane is

    • A) sp
    • B) sp²
    • C) sp³
    • D) dsp²

    Answer: sp³

    Explanation: Methane (CH4) has a tetrahedral geometry, corresponding to sp³ hybridization.

12. Question 12

    Q12. The IUPAC name for (CH3)3CCH2CH3 is

    • A) 2,2-Dimethylbutane
    • B) 3,3-Dimethylbutane
    • C) 2,2-Dimethylpentane
    • D) 3,3-Dimethylpentane

    Answer: 2,2-Dimethylpentane

    Explanation: The compound is named based on the longest carbon chain and substituents.

13. Question 13

    Q13. The compound that contains both sp² and sp³ hybridized carbon atoms is

    • A) 1,3-Butadiene
    • B) Propene
    • C) Propyne
    • D) Propane

    Answer: Propene

    Explanation: Propene has a double bond (sp²) and a single bonded carbon (sp³).

14. Question 14

    Q14. The general formula for alkanes is

    • A) CnH2n+2
    • B) CnH2n
    • C) CnH2n-2
    • D) CnHn

    Answer: CnH2n+2

    Explanation: Alkanes follow the general formula CnH2n+2, where n is the number of carbon atoms.

15. Question 15

    Q15. The hybridization of the oxygen atom in water is

    • A) sp
    • B) sp²
    • C) sp³
    • D) dsp²

    Answer: sp³

    Explanation: The oxygen atom in water is sp³ hybridized, with two lone pairs and two bonded pairs.

16. Question 16

    Q16. The major product of the nitration of benzene is

    • A) Nitrobenzene
    • B) Dinitrobenzene
    • C) Trinitrobenzene
    • D) Phenol

    Answer: Nitrobenzene

    Explanation: The nitration of benzene primarily yields nitrobenzene due to the directing effect of the benzene ring.

17. Question 17

    Q17. The type of bond between the carbon atoms in ethyne is

    • A) Single
    • B) Double
    • C) Triple
    • D) Ionic

    Answer: Triple

    Explanation: Ethyne (acetylene) has a triple bond between the carbon atoms.

18. Question 18

    Q18. The reaction of alkyl halides with NaI in acetone is an example of

    • A) SN1 reaction
    • B) SN2 reaction
    • C) E1 reaction
    • D) E2 reaction

    Answer: SN2 reaction

    Explanation: The reaction is an SN2 reaction, favored by the polar aprotic solvent acetone.

19. Question 19

    Q19. The functional group present in an ether is

    • A) -OH
    • B) -CHO
    • C) -O-
    • D) -COOH

    Answer: -O-

    Explanation: Ethers are characterized by the -O- functional group linking two alkyl groups.

20. Question 20

    Q20. The IUPAC name for CH3CH2CH2CHO is

    • A) Butanal
    • B) Propanone
    • C) Butanone
    • D) Propanal

    Answer: Butanal

    Explanation: The compound is named based on the longest carbon chain containing the aldehyde group.