Q 1 :

Methyl group attached to a positively charged carbon atom stabilizes the carbocation due to          [2024]

• –$\mathrm{I}$ inductive effect

   

• electromeric effect

   

• hyperconjugation

   

• mesomeric effect

   

Q 2 :

The most stable carbocation among the following is               [2024]

 

Q 3 :

Given below are two statements:
Statement I: In an organic compound, when inductive and electromeric effects operate in opposite directions, the inductive effect predominates.
Statement II: Hyperconjugation is observed in o-xylene.

In the light of the above statements, choose the correct answer from the options given below:            [2023]

• Statement I is true but Statement II is false.

   

• Statement I is false but Statement II is true.

   

• Both Statement I and Statement II are true.

   

• Both Statement I and Statement II are false.

   

Q 4 :

A tertiary butyl carbocation is more stable than a secondary butyl carbocation because of which of the following?          [2020]

• –$\mathrm{I}$ effect of –${\mathrm{CH}}_3$ groups

   

• +R effect of –${\mathrm{CH}}_3$ groups

   

• –R effect of –${\mathrm{CH}}_3$ groups

   

• Hyperconjugation

   

Q 5 :

The most stable carbocation, among the following is:              [2019]

• ${\left({\mathrm{CH}}_3\right)}_3\mathrm{C}-\stackrel{+}{\mathrm{C}}\mathrm{H}-{\mathrm{CH}}_3$

   

• ${\mathrm{CH}}_3-{\mathrm{CH}}_2-\stackrel{+}{\mathrm{C}}\mathrm{H}-{\mathrm{CH}}_2-{\mathrm{CH}}_3$

   

• ${\mathrm{CH}}_3-\stackrel{+}{\mathrm{C}}\mathrm{H}-{\mathrm{CH}}_2-{\mathrm{CH}}_2-{\mathrm{CH}}_3$

   

• ${\mathrm{CH}}_3-{\mathrm{CH}}_2-\stackrel{+}{\mathrm{C}}{\mathrm{H}}_2$

   

Q 6 :

Which of the following carbocations is expected to be most stable?          [2018]

Q 7 :

The correct statement regarding electrophile is             [2017]

• electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from another electrophile

   

• electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile

   

• electrophile can be either neutral or positively charged species and can form a bond by accepting a pair of electrons from a nucleophile

   

• electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from a nucleophile.

   

Q 8 :

Which of the following statements is not correct for a nucleophile?            [2015]

• Ammonia is a nucleophile.

   

• Nucleophiles attack low ${\mathrm{e}}^{-}$ density sites.

   

• Nucleophiles are not electron seeking.

   

• Nucleophile is a Lewis acid.

   

Q 9 :

Treatment of cyclopentanone  with methyl lithium gives which of the following species?         [2015]

• Cyclopentanonyl radical

   

• Cyclopentanonyl biradical

   

• Cyclopentanonyl anion

   

• Cyclopentanonyl cation

   

Q 10 :

Which of the following is the most correct electron displacement for a nucleophilic reaction to take place?         [2015]

Q 11 :

Consider the following compounds:                              

Hyperconjugation occurs in                                 [2015]

• III only

   

• I and III

   

• I only

   

• II only

   

Q 12 :

In which of the following compounds, the $\mathrm{C}-\mathrm{Cl}$ bond ionisation shall give most stable carbonium ion?           [2015]

Q 13 :

The incorrect statement regarding chirality is:      [2022]

• A racemic mixture shows zero optical rotation.

   

• S_N1 reaction yields 1 : 1 mixture of both enantiomers.

   

• The product obtained by S_N2 reaction of haloalkane having chirality at the reactive site shows inversion of configuration.

   

• Enantiomers are superimposable mirror images on each other