Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Haloalkanes and Haloarenes question

2014 · Shift 0 · Q16
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Chemistry
  4. /Haloalkanes and Haloarenes
  5. /2014 · Shift 0 · Q16

Haloalkanes and Haloarenes question

2014 · Shift 0 · Q16

JEE MainChemistryHaloalkanes and HaloarenesMCQ+4 / −1
In SN2SN_2SN2​ reactions, the correct order of reactivity for the following compounds: CH3ClCH_3ClCH3​Cl, CH3CH2ClCH_3CH 2ClCH3​CH2Cl, (CH3)2CHCl(CH_3)_2CHCl(CH3​)2​CHCl and (CH3)3CCl(CH_3)_3CCl(CH3​)3​CCl is:
  1. A
    CH3CH2ClCH_3CH_2ClCH3​CH2​Cl > CH3ClCH_3ClCH3​Cl > (CH3)2CHCl(CH_3)_2CHCl(CH3​)2​CHCl > (CH3)3CCl(CH_3)_3CCl(CH3​)3​CCl
  2. B
    (CH3)2CHCl(CH_3)_2CHCl(CH3​)2​CHCl > CH3CH2ClCH_3CH_2ClCH3​CH2​Cl > CH3ClCH_3ClCH3​Cl > (CH3)3CCl(CH_3)_3CCl(CH3​)3​CCl
  3. C
    CH3ClCH_3ClCH3​Cl > (CH3)2CHCl(CH_3)_2CHCl(CH3​)2​CHCl > CH3CH2ClCH_3CH_2ClCH3​CH2​Cl > (CH3)3CCl(CH_3)_3CCl(CH3​)3​CCl
  4. D
    CH3ClCH_3ClCH3​Cl > CH3CH2ClCH_3CH_2ClCH3​CH2​Cl > (CH3)2CHCl(CH_3)_2CHCl(CH3​)2​CHCl > (CH3)3CCl(CH_3)_3CCl(CH3​)3​CCl
View written solutionFree

Correct answer: D

  1. In an SN2S_N2SN​2 reaction, the nucleophile attacks the carbon bearing the leaving group from the backside.

  2. Therefore, the rate of an SN2S_N2SN​2 reaction depends strongly on steric hindrance around that carbon.

  3. Less substituted alkyl halides react faster in SN2S_N2SN​2: methyl>1∘>2∘≫3∘\text{methyl} > 1^\circ > 2^\circ \gg 3^\circmethyl>1∘>2∘≫3∘

  4. Now compare the given compounds:

  • CH3ClCH_3ClCH3​Cl = methyl chloride ⇒\Rightarrow⇒ least hindered
  • CH3CH2ClCH_3CH_2ClCH3​CH2​Cl = primary alkyl chloride
  • (CH3)2CHCl(CH_3)_2CHCl(CH3​)2​CHCl = secondary alkyl chloride
  • (CH3)3CCl(CH_3)_3CCl(CH3​)3​CCl = tertiary alkyl chloride ⇒\Rightarrow⇒ most hindered

  1. Hence the correct reactivity order in SN2S_N2SN​2 is: CH3Cl>CH3CH2Cl>(CH3)2CHCl>(CH3)3CClCH_3Cl > CH_3CH_2Cl > (CH_3)_2CHCl > (CH_3)_3CClCH3​Cl>CH3​CH2​Cl>(CH3​)2​CHCl>(CH3​)3​CCl

  2. Checking options:

  • A: wrong
  • B: wrong
  • C: wrong
  • D: correct

Therefore, the correct option is D.

PreviousNext

More from Haloalkanes and Haloarenes

  • The major organic compound formed by the reaction of 1, 1, 1– trichloroethane with silver powder is:2014 · MCQ
  • A solution of (–l) – chloro –1 – phenylethane in toluene racemises slowly in the presence of a small amount of SbCl5​, due to the formation of :2013 · MCQ
  • Compound (A),C8​H9​Br, gives a white precipitate when warmed with alcoholic AgNO3​. Oxidation of (A) gives an acid (B),C8​H6​O4​.(B) easily forms anhydride on…2013 · MCQ
  • Iodoform can be prepared from all except :2012 · MCQ
  • What is DDT among the following?2012 · MCQ
  • How many chiral compounds are possible on monochlorination of 2–methyl butane ?2012 · MCQ
  • Consider the following bromides : The correct order of SN​1 reactive is Includes diagram2010 · MCQ
  • Which of the following on heating with aqueous KOH, produces acetaldehyde ?2009 · MCQ