You can't ignore halogen

Chemistry Level 2

The SN1 reaction is a substitution reaction in organic chemistry. "SN" stands for nucleophilic substitution and the "1" represents the fact that the rate-determining step is unimolecular. Thus, the rate equation is often shown as having first-order dependence on electrophile and zero-order dependence on nucleophile. Regarding product we know we get two types of products ie. retention & inversion than

Which of these is correct regarding Sn1 reaction?

A. Both inversion and retention product are formed in same amount

B. Inversion product is slightly less than retention product

C. Retention product is slightly less than inversion product

B C A Can't say

2 solutions

Atul Shivam
Dec 22, 2016

The carbocation intermediate formed in the reaction's rate determining step is an sp2 hybridized carbon with trigonal planar molecular geometry. This allows two different avenues for the nucleophilic attack, one on either side of the planar molecule, but if we look at it halide ion provide hindrence to the Nucleophile resulting slightly more products of inversion than retention.

Hence option C. Retention product is slightly less than inversion product is correct

K T
Jul 21, 2019

In as $S_N1$ reaction the original halogenated organic molecule first releases the old halogen ion and becomes a carbokation. It then recombines with a new halogen ion. If the new ion approaches from the other side as the original ion, this causes the spatial structure to invert. If the new ion approaches from the same side as the original ion, the structure is retained.

Because the leaving and entering ions repel, so hamper one another, retention is slightly less probable to occur than inversion.

Also see https://youtu.be/svLMt-Do3NE

You can't ignore halogen

2 solutions

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