CHEMISTRY COMMUNITY

in #28 in Chapter 4 of the organic textbook, you have to write the mechanism and the transition state
I understood it except this part:

why is the positive dipole on the middle carbon as opposed to the carbon forming the bond with the H?

Think about the structures before and after the first transition state.

Before the transition state, both HBr and CH3CHCH2 are neutral. After the transition state, Br- has a negative charge and CH3C+CH3 has a positive charge on the central carbon.

The transition state should be between these two states, and so the Br should have a partial negative charge in the TS and the central carbon should have a partial positive in the TS.