Nucleophilic Substitution Reaction (between Alkyl halide & Ammonia)Watch this thread
I'm not sure about the structure of tetraethylammonium bromide.
Is this what happens in the last step?
Carbon and Bromine bond breaks by homolytic fission.
Nitrogen has a positive charge, because it lost an electron to Bromine. Bromine becomes negative, by gaining the electron.
I'd personally use curly arrows if I wanted to show the mechanism. So for example with the first step: one from the electron pair on the nitrogen to the carbon and then from the C-B bond to the bromine
Otherwise looks good