3. List three characteristics of a substitution reaction that would indicate whe

Question

3. List three characteristics of a substitution reaction that would indicate whether substitution occurs via SN1 or SN2 mechanism and explain your reasoning 4. Draw the potential energy diagram for the reaction of 2-methyl-2-butanol with Cl under acid (HC) catalyzed reaction condition. (1)Label the structures of the (a) reactants, (b) intermediates, e transition states, (d) products, and (e) activation energies (Es) for each step. (2) Which step is the rate-determining step? (3) Identify the electrophile and nucleophile in each step when applicable.

Explanation / Answer

The three characteristic factors which decides the fate of the reaction ie it will occurs through SN1 or SN2 mechanism are:

1) WHETHER THE ALKYL HALIDE IS METHYL (CH3X) , PRIMARY, SECONDARY or TERTIARY - - - - - - - >

if CH3X or primary - - - - - > then reaction proceeds via SN2 mechanism because the lesser the hinderance thus more easily for nucleophile to attack the carbon centre, ie oreder of reactivity is:

Tertiary < secondary < primary < CH4X

If tertiary group - - - - > Then it will goes by SN1 mechanism because of the higher stability of tertiary carbocation, ie the order for reactivity is :

CH4X < Primary < secondary < tertiary

2)

NUCLEOPHILE - - - - - - > Now, consider secondary alkyl halide if the nucleophile is strong the reaction will goes by SN2 mechanism because to replace the existing nucleophile the incoming nucleophile should be stronger.

And, if its moderate or weak nucleophile the reaction proceeds via SN1 mechanism.

3)

SOLVENT - - - - - > If the reaction occurs in polar aprotic solvent then reaction proceeds via SN2 mechanism

And, If the reaction occurs in polar protic solvent then reaction proceeds via SN2 mechanism.

  

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.