Final answer:
The mechanism described is a nucleophilic substitution bimolecular (SN2) reaction, characterized by an inversion of stereochemistry and simultaneous bond-making and bond-breaking.
Step-by-step explanation:
The pattern of arrow pushing described in the student's question indicates a nucleophilic substitution bimolecular mechanism, also known as SN2. In this mechanism, the incoming nucleophile approaches the electrophilic carbon atom from the side opposite to the leaving group, leading to a simultaneous bond-making with the nucleophile and bond-breaking with the leaving group. The result is an inversion of stereochemistry at the carbon atom, which is a characteristic feature of the SN2 reaction mechanism.