Arrange the following CH3CH2CH2Cl (I) , CH3CH2-CHCl-CH3 (II) , (CH3)2CHCH2Cl (III) and (CH3)3C—Cl (IV) in order of decreasing tendency towards SN2 reactions

Question

Arrange the following CH3CH2CH2Cl (I) , CH3CH2-CHCl-CH3 (II) , (CH3)2CHCH2Cl (III) and (CH3)3C—Cl (IV) in order of decreasing tendency towards SN2 reactions (A) I > III > II > IV (B) III > IV > II > I (C) II > I > III > IV (D) IV > III > II > I

Tardigrade Admin · Accepted Answer

In SN2 reactions, the attack of nucleophile occurs from the back side on the carbon atom carrying the halogen. Therefore, presence of bulky substituents on or near this carbon atom tends to hinder the approach of the nucleophile to the a-carbon due to steric hindrance and thus makes the reaction difficult to occur. Thus, the reactivity in SN2 reactions follows the following order CH3CH2CH2Cl (I) > (CH3)2CHCH2Cl (III) > CH3 -CH2-CHCl-CH3 (II) > (CH3)3C-Cl(IV).

Q. Arrange the following CH3​CH2​CH2​Cl(I) , CH3​CH2​−CHCl−CH3​(II) , (CH3​)2​CHCH2​Cl(III) and (CH3​)3​C—Cl(IV) in order of decreasing tendency towards SN​2 reactions

I > III > II > IV

III > IV > II > I

II > I > III > IV

IV > III > II > I

Q. Arrange the following $C H_{3} C H_{2} C H_{2} Cl (I)$ , $C H_{3} C H_{2} - C H Cl - C H_{3} (II)$ , $(C H_{3})_{2} C H C H_{2} Cl (III)$ and $(C H_{3})_{3} C — Cl (I V)$ in order of decreasing tendency towards $S_{N} 2$ reactions