Question

10. (2 pts) Draw the structure of the transition state for the following reaction: C + H, at 0lt2

Please help me correct the wrong answer. If you could also tell me what I did wrong that would be fantastic, thank you!

Answer 1

One water molecule is being eliminated. In the reactant molecule, there is an OH2 group with a + charge on O. A + charge on O is already unstable, and O will want to remove it. It can do so by taking up the electrons in the bond (and thus neutralising it's + charge). This will result in breaking the bond, and neutral water will leave, while the C which was bonded to O will now have a + charge (since O took the bonding electrons with it).

H20 OH Transition Shate This bond bneaks,fakes e mthe bond, and 20( leavivg grou leaves T

The transition state will thus have the C-O bond breaking.

The electrons in the bond are going away from C. So, in the transition state, C will have δ+ charge. The O will get the δ- charge.

However, here, O already has 1 + charge. You can imagine the δ charge to be equivalent to a half charge. So, O will overall have +1 -δ charge = +δ charge. Thus, in the transition state , both O and C will have + δ charge. The total charge in transition state will then be 2 x (+δ) = +1 charge. This is equal to total charge on the reactant and product side too (the total charge on reactants, transition state and products must always be same).

Hence, the structure of the transition state is: