Question

Choose the compound from the following that will react fastest by SN1 mechanism.
a. 1-iodobutane
b. 1-iodopropane
c. 2-iodo-2 methylbutane
d. 2-iodo-3-methylbutane​

Answer 1

Answer:

The more stable the carbocation is, the easier it is to form, and the faster the SN1 reaction will be. Some students fall into the trap of thinking that the system with the less stable carbocation will react fastest, but they are forgetting that it is the generation of the carbocation that is rate determining.

Explanation:

hope this helps

Answer 2

Answer:

The Correct Answer would be c. 2-iodo-2-methylbutane. Among the following compounds, the one that will undergo substitution reaction by SN1 mechanism is 2-iodo-2-methylbutane.

Explanation:

For a substitution reaction to undergo the reaction through SN1 mechanism, it is necessary that must be forming stable carbocation in the reaction. The one forming most stable carbocation would eventually undergo substitution fastest by SN1.

Now, for 2-iodo-2-methylbutane, the intermediate carbocation formed would be a tertiary carbon atom. As the stability goes in order from tertiary > secondary > primary, hence, it will react fastest by SN1 mechanism.