The electrophilic aromatic substitution proceeds through a:

(1) free radical

(2) sigma complex

(3) benzyne

(4) carbene

Which of the following substitution of benzene is ortho-para in electrophilic substitution and ortho-para in nucleophilic substitution ?

(1) -NO₂

(2) -NO

(3) -SO₃H

(4) -SO₂Me

Which one of the following undergoes nucleophilic aromatic substitution at the fastest rate?
(1) 

(2) 

(3) 

(4) 

Many organic compounds are prepared by using PCl₅ because:

(1) OH group of alcohol is easily replaced by chlorine atom

(2) chlorines are added to the unsaturated compounds

(3) it removes water from organic compounds

(4) phosphorus atoms are entered in the alcohol

identify the product in the given reaction:

${\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2+\mathrm{NOCl}\to \mathrm{product}$

1. ${\mathrm{CH}}_3\mathrm{CHCl}·\mathrm{CH}2·\mathrm{NO}$

2. ${\mathrm{CH}}_3\mathrm{CH}\left(\mathrm{NO}\right)·{\mathrm{CH}}_2\mathrm{Cl}$

3. ${\mathrm{CH}}_3\mathrm{CHCH}\left(\mathrm{Cl}\right)\left(\mathrm{NO}\right)$

4. ${\mathrm{CH}}_2\left(\mathrm{NO}\right)·{\mathrm{CH}}_2·{\mathrm{CH}}_2\mathrm{Cl}$

Common oxidizing agents used in organic chemistry are;

1. Fenton's reagent

2. osmium tetroxide

3. acidified KMnO₄

4. all are correct

 3-methyl-2-pentene on reaction with HOCl gives:

1. 

2. 

3. 

4. 

In E₂ elimination, some compounds follow Hofmann's rule which means:

1. the double bond goes to the most substituted carbon

2. the compound is resistant to elimination

3. no double bond is formed

4. the double bond goes mainly towards the least substituted carbon

The hydrolysis of alkyl halides by aqueous NaOH is best termed as:

(1) electrophilic substitution reaction

(2) electrophilic addition reaction

(3) nucleophilic addition reaction

(4) nucleophilic substitution reaction

S_N1 reaction on optically active substrates mainly gives:

1. Retention in configuration

2. Inversion in configuration

3. Racemic product

4. No product is obtained