Question

During 2nd step of SN1 mechanism hybridization of C changes from
a)sp3 to sp2
b)sp2 to sp3
c)sp to sp3
d)none

Answer 1

The SN1 reaction takes place in three steps: Formation of a cation when the leaving group is separated from the molecule (this is a reversible step). At this point, the central carbon changes from a sp3 hybridization to a sp2 hybridization because it is now a carbocation forming only three bonds.

Answer 2

Answer: b. Sp2 to Sp3

Exp: In the second step of S.N.1 Mechanism, The 3° carbocation reacts with OH⁻(Nucleophile) and forms product.

Step II : Attack of Nucleuophile:

       Ch₃                        Ch₃

         |                              |

Ch₃ - C⁺ + OH⁻ ⇒ Ch₃ - C - OH

          |                             |

         Ch₃                       Ch₃

Here, As we can see the C which was Sp2 hybridised turned into Sp3. (The carbocation does not make any difference while measuring the hybridisation, only sigma bonds and lone pair makes the difference in hybradisation.)