Final answer:
A proton transfer reaction is depicted with arrows pointing from the electron pair on the base to the proton from the acid, leading to the formation of a product such as water. A Lewis acid-base reaction, on the other hand, involves the donation of an electron pair from the base to the acid without involving protons, forming an adduct.
Step-by-step explanation:
The question at hand involves a proton transfer reaction, which is a key concept in acid-base chemistry. A proton transfer reaction typically involves the transfer of a proton (H+) from an acid to a base. When drawing the curved arrows for such a reaction, the arrows should point from the electron pair on the base to the proton that is being transferred. In the case of the reaction between a hydronium ion, H3O+, and a hydroxide ion, OH-, the curved arrow would indicate the electron pair on the hydroxide ion moving towards and bonding with the proton from the hydronium ion, resulting in the formation of two molecules of water (H2O).
For a Lewis acid-base reaction, which does not involve protons, an example could be the reaction between ammonia (NH3) as the Lewis base and boron trifluoride (BF3) as the Lewis acid. In this case, the nitrogen atom in ammonia donates an electron pair to the boron atom in boron trifluoride, creating an adduct.