The order of decreasing ease of abstraction of hydrogen atoms in

Subject

Chemistry

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

31.

Among the following structures the one which is not a resonating structure of others is

            

  • I

  • II

  • III

  • IV


32.

Among the following compounds, the one(s) that gives (give) effervescence with aqueous NaHCO3 solution is (are)

(CH3CO)2 O           CH3COOH         PhOH          CH3COCHO

   I                           II                   III                 IV

  • I and II

  • I and III

  • Only II

  • I and IV


33.

The 4th higher homologue of ethane is

  • butane

  • pentane

  • hexane

  • heptane


34.

Among the following, the one which is not a "green house gas", is

  • N2O

  • CO2

  • CH4

  • O2


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35.

Metal ion responsible for the Minimata disease is

  • Co2+

  • Hg2+

  • Cu2+

  • Zn2+


36.

The most likely protonation site in the following molecule is    

                        

 

  • C-1

  • C-2

  • C-3

  • C-6


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37.

The order of decreasing ease of abstraction of hydrogen atoms in the following molecules

  • Ha > Hb > Hc

  • H> H > Hb

  • Hb > H> Hc

  • Hc > Hb > Ha


B.

H> H > Hb

Abstraction of (Ha) hydrogen atom results in the formation of 3° allylic carbocation whereas abstraction of He gives 2° allylic carbocation (which is less stable as compared to former one). However, abstraction of Hb gives only a 2° carbocation which is less stable as compared to former two. More the stability of generated carbocation, higher is the tendency of abstraction of hydrogen. Thus. the order of decreasing ease of abstraction of hydrogen atoms from the given molecule is

             Ha > Hc > Hb


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38.

Among the following statements about the molecules X and Y, the one(s) which correct is (are)

                

  

  • X and Y are diastereomers

  • X and Y are enantiomers

  • X and Y are both aldohexoses

  • Xis a D-sugar and Y is an L-sugar


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39.

The rate of a certain reaction is given by, rate = k [H+]n. The rate increases 100 times when the pH changes from 3 to 1. The order (n) of the reaction is

  • 2

  • 0

  • 1

  • 1.5


40.

If Cl2 is passed through hot aqueous NaOH, the products formed have Cl in different oxidation states. These are indicated as

  • -1 and +1

  • -1and +5

  • +1 and +5

  • -1and +3


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