Bromination of (E)-2-butenedioic acid gives

(1) (2R, 3S)-2, 3-dibromosuccinic acid

(2) (2R, 3R)-2, 3-dibroniosuccinic acid

(3) a mixture of (2R, 3R) and (2S, 3S)-2, 3-dibromosuccinic acid

(4) (2S, 3S)-2, 3-dibromosuccinic acid

Consider the following reaction:-

Which response contains all the correct statement about this process?
(1)Dehydration
(2)E₂ mechanism
(3)Carbon skeleton migration
(4)Most stable alkene will form
(5)Single-step reaction

(a)1,3        (b)1,2,3         (c)1,2,5          (d)1,3,4

$\underset{\mathrm{heat}}{\overset{{\mathrm{H}}_3{\mathrm{PO}}_4}{\to }} \mathrm{OH} +$

$\stackrel{\mathrm{HBr}}{\to }\left(\mathrm{X}\right) \underset{\mathrm{acetone}}{\overset{\mathrm{NaI}}{\to }}\left(\mathrm{Y}\right) \left(\mathrm{Major}\right)$; Product (Y) is:

(1) cis-2-butene                                 

(2) trans-2-butene

(3) 1-butene                                   

(4) Iso-butene

Which position will be attacked most rapidly by the nitronium ion (-NO₂)⁺ when the compound undergoes nitration with HNO₃/H₂SO₄ :-

1. A

2. B

3. C

4. D

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