Out ofRelative stabilities order is from Chemistry JEE Year 2013

Subject

Chemistry

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

41.

In the reaction sequence,

X is

  • cyclohexanone

  • caprolactum

  • HO(CH2)6NH2

  • Hexamethyllne disocyanate


42.

A positive carbylamine test is given by

I. N, N-dimethylaniline

II. 2, 4-dimethylamine

III. N-methyl-o-methylaniline

IV. p-methylbenzyl amine

  • (II) and (IV)

  • (I) and (IV)

  • (II) and (III)

  • (I) and (II)


43.

Identify the final product B of the reaction

C6H5COOH + NaHC*O3 → gas (A) H2O+CH3MgBr (B)

Here, C* = C14

  • C*H3COOH

  • C6H5C*OOH

  • CH3C*OOH

  • HC*OOCH3


44.

The reactant X in the reaction

(CH3CO)2OCH3COONa Cinnamic acid is


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45.

The compound B is


46.

CH3CHO + HCHO HeatDil. NaOH A H3O+HCN B

The structure of the compound B is

  • CH2=CH-CH(OH)-COOH

  • CH2=CH-CH(CN)-OH

  • CH3-CH2-CN(CN)OH

  • CH3-CH||ClCN-COOH


47.

Which of the following compounds is most acidic?

  • Cl-CH2-CH2-OH


48.

Phenol + CCl4 + KOH → X; 

Which of the following statement is true for X?

  • It gives effervescence with NaHCO3

  • Gives silver mirror with Tollen's reagent

  • Does not give the red colour with FeCl3

  • All of the above


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49.

Which of the following is bacteriostatic?

  • Penicillin

  • Erythromycin

  • Aminoglycoside

  • Ofloxacin


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50.

Out of

Relative stabilities order is

  • 4 < 2 < 3 < 1

  • 2 > 4 < 3 < 1

  • 4 < 2 < 1 < 3

  • 2 < 4 < 1 < 3


A.

4 < 2 < 3 < 1

Due to the presence of phenyl group the stabihties of the carbocations 1, 2 and 3 are greater than cation 4, (due to resonance). Further the presence of electron-donating groups on phenyl ring increases the stability of carbocation.

Hence, cation 1 and 3 are more stable than cation 2. Moreover - OMe group shows +M effect which is more prominent than +I effect of -Me group. Thus, cation 1 is more stable than cation 3. So, the correct order is, 4 < 2 < 3 < 1.


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