Arrange these in the correct order of their reactivity during nucleophillic substitution by SN2 and SN1 conditions, Ch3-CH=CH-CH2-Cl, Ch3-CCl-Ch-Ch3, and Ch3-Ch2-Ch2-Ch2-Cl
The double bound will come first follow by the one that have the chlorine atom at the last hydrogen atom follow by the middle one i.e. 1 3 2
To determine the reactivity of these compounds in nucleophilic substitution reactions, we need to consider the factors that affect the reaction mechanism and rate. In SN2 (substitution nucleophilic bimolecular) reactions, the reaction occurs in a single step and involves a direct attack of the nucleophile on the substrate. In SN1 (substitution nucleophilic unimolecular) reactions, the reaction proceeds through a carbocation intermediate before being attacked by the nucleophile. The rate-determining step in SN1 reactions is the formation of the carbocation.
Now let's analyze the given compounds:
1. CH3-CH=CH-CH2-Cl: This compound contains a carbon-carbon double bond (alkene) in addition to the leaving group (chlorine). The presence of an alkene makes the compound less reactive in both SN1 and SN2 reactions. Alkene groups tend to stabilize the alkyl halides by conjugation, making them less prone to undergoing nucleophilic substitution reactions. Therefore, this compound is the least reactive among the three.
2. CH3-CCl-CH-Ch3: This compound contains a tertiary carbon, which is more stable than primary or secondary carbons due to the increased number of alkyl groups attached to it. Tertiary carbons form more stable carbocation intermediates, making this compound more reactive in SN1 reactions. However, in SN2 reactions, the steric hindrance caused by the three alkyl groups attached to the carbon makes the reaction slower. So, overall, this compound would be intermediate in reactivity.
3. CH3-Ch2-Ch2-Ch2-Cl: This compound contains a primary carbon, which is less stable than secondary or tertiary carbons. It will readily undergo SN2 reactions because the primary carbon does not have much steric hindrance, allowing the nucleophile to attack easily. However, it is slower in SN1 reactions due to the less stable carbocation formation on a primary carbon. Therefore, this compound is the most reactive among the three.
Thus, arranging them in the correct order of reactivity from highest to lowest, we have: CH3-Ch2-Ch2-Ch2-Cl > CH3-CCl-CH-Ch3 > CH3-CH=CH-CH2-Cl.