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Basics of Organic Chemistry question

2024 · 31 Jan · Shift 2 · Q7
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Basics of Organic Chemistry question

2024 · 31 Jan · Shift 2 · Q7

JEE MainChemistryBasics of Organic ChemistryMCQ+4 / −1
Identify structure of 2,3-dibromo-1-phenylpentane.
  1. A
    JEE Main 2024 (Online) 31st January Evening Shift Chemistry - Basics of Organic Chemistry Question 76 English Option 1
  2. B
    JEE Main 2024 (Online) 31st January Evening Shift Chemistry - Basics of Organic Chemistry Question 76 English Option 2
  3. C
    JEE Main 2024 (Online) 31st January Evening Shift Chemistry - Basics of Organic Chemistry Question 76 English Option 3
  4. D
    JEE Main 2024 (Online) 31st January Evening Shift Chemistry - Basics of Organic Chemistry Question 76 English Option 4
View written solutionFree

Correct answer: C

  1. Parse the IUPAC name

    The compound is 2,3-dibromo-1-phenylpentane.

    Let us break it into parts:

    • Parent chain: pentane ⇒\Rightarrow⇒ a 5-carbon straight chain.
    • Substituent at carbon 1: phenyl
    • Substituents at carbons 2 and 3: bromo
  2. Write the pentane chain with numbering

    C1−C2−C3−C4−C5\mathrm{C_1 - C_2 - C_3 - C_4 - C_5}C1​−C2​−C3​−C4​−C5​

  3. Place the substituents

    • At C1C_1C1​: phenyl group (C6H5−)\left(\mathrm{C_6H_5-}\right)(C6​H5​−)
    • At C2C_2C2​: Br
    • At C3C_3C3​: Br
  4. Construct the condensed structure

    Start from carbon 1:

    • C1C_1C1​ is attached to phenyl and to C2C_2C2​, so it is CH2Ph\mathrm{CH_2Ph}CH2​Ph
    • C2C_2C2​ has Br, so it is CH(Br)\mathrm{CH(Br)}CH(Br)
    • C3C_3C3​ has Br, so it is CH(Br)\mathrm{CH(Br)}CH(Br)
    • C4C_4C4​ is CH2\mathrm{CH_2}CH2​
    • C5C_5C5​ is CH3\mathrm{CH_3}CH3​

    Therefore the structure is:

    C6H5−CH2−CH(Br)−CH(Br)−CH2−CH3\mathrm{C_6H_5-CH_2-CH(Br)-CH(Br)-CH_2-CH_3}C6​H5​−CH2​−CH(Br)−CH(Br)−CH2​−CH3​

  5. Match with the options

    The correct option must represent:

    Ph−CH2−CHBr−CHBr−CH2−CH3\boxed{\mathrm{Ph-CH_2-CHBr-CHBr-CH_2-CH_3}}Ph−CH2​−CHBr−CHBr−CH2​−CH3​​

    This corresponds to Option C.

  6. Comparison with stored answer

    Stored correct answer: C

    Derived answer: C

    Hence, the derived answer agrees with the stored answer.

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