COMPASSLearning
RegisterLogin

CBSE Class 12 · 2017 · Haloalkanes and HaloarenesShort Answer

WhatsApp Email
(a) Identify the chiral molecule in the pair shown in the figure (3-methylbutan-2-ol and 2,4-dimethylpentan-3-ol).
(b) Write the structure of the product when chlorobenzene is treated with methyl chloride in the presence of sodium metal and dry ether.
(c) Write the structure of the alkene formed by dehydrohalogenation of 1-bromo-1-methylcyclohexane with alcoholic KOH.
Structure (i) 3-methylbutan-2-ol
(i) 3-methylbutan-2-ol
Structure (ii) 2,4-dimethylpentan-3-ol
(ii) 2,4-dimethylpentan-3-ol

Solution

(a) In 3-methylbutan-2-ol, CH–\*CH(OH)–CH(CH), the carbinol carbon holds CH, OH, H and isopropyl — four different groups ⇒ \textbf{chiral}. 2,4-Dimethylpentan-3-ol is symmetric about C-3 (two identical isopropyls) — achiral.
(b) Wurtz–Fittig reaction:

(c) Alcoholic KOH removes a β-H; by Saytzeff the ring double bond forms toward the more substituted side:

CBSE Class 12 Board · 2017 · Subjective

Practise more: all CBSE board PYQs on Haloalkanes and Haloarenes →

More board questions on Haloalkanes and Haloarenes

  1. Auto-oxidation of chloroform in air and light produces a poisonous gas known as:
    CBSE 2024View solution →
  2. Assertion (A): Inversion of configuration is observed in the S2 reaction.
    Reason (R): The reaction proceeds with the formation of a carbocation.
    CBSE 2024View solution →
  3. Account for the following:
    (a) Haloalkanes react with AgCN to form isocyanides as the main product.
    (b) Allyl chloride shows high reactivity towards the S1 reaction.
    (c) Haloarenes are extremely less reactive towards nucleophilic substitution reactions.
    CBSE 2024View solution →
  4. Write equations for the following:
    a) oxidation of chloroform by air and light
    b) reaction of chlorobenzene with CHCl / anhydrous AlCl
    CBSE 2023View solution →
  5. The substitution reaction of an alkyl halide mainly occurs by the SN1 or SN2 mechanism. Whatever mechanism alkyl halides follow for the substitution reaction to occur, the polarity of the carbon-halogen bond is responsible for these substitution reactions. The rate of SN1 reactio …
    CBSE 2020View solution →
  6. The substitution reaction of an alkyl halide mainly occurs by the SN1 or SN2 mechanism. Whatever mechanism alkyl halides follow for the substitution reaction to occur, the polarity of the carbon-halogen bond is responsible for these substitution reactions. The rate of SN1 reactio …
    CBSE 2020View solution →