Question

Which of the following is incorrect statement for the given reaction?

• A. Rate of formation of II and IV would be identical
• B. Rate of formation of I would be slower than that of III
• C. Formation of I would show primary isotope effect
• D. Formation of III involves E1 reaction

Answer 1

The correct option is D Formation of III involves E1 reaction

Rate of formation of II and IV are similar because it goes by substitution reaction where $C-H$ and $C-D$ bond breaking is not involved.

I and III are products of elimination reaction where $C-H$ and $C-D$ bond breaking is the part of RDS.
Breaking of $C-D$ bond is difficult compare to $C-H$ due to higher mass of $D$.
Hence, rate in I is slower than III due to isotopic effect of $D$

It undergo via E2 not E1 because carbocation is not stable and alcoholic KOH is a strong base.