# Write the overall reaction for reaction of methyl benzoate with excess phenyl magnesium brimide in ether, followed by H3O+. ????

3. Electron conjugation from the newly-formed hydroxyl group's oxygen forces the methoxy leaving group to break off, a rapid intramolecular process. The pKa of methanol is about $15.5$, but the pKa of benzene is about $43$, so there is pretty much no chance ($1$ in 10^27.5) of the phenyl group breaking back off.
4. The reaction finishes when the methanolate grabs the proton off of the protonated final product. The methanolate does so rather than the water (${10}^{6.1}$ times as often), since the pKa of methanol (~15.5) is greater than the pKa of hydronium (~9.4), and acid-base equilibrium lies on the side of the weaker acid or stronger base.