When new oceanic lithosphere is generated at an oceanic ridge, what happens to the two plates on either side of the ridge?

The two plates becomes larger

Explanation:

The mid-oceanic ridges are the landforms that are formed at the divergent plate boundaries, and these represent the spreading zone. The magma below the earth's crust becomes so hot and pushes upward with great force, as a result of which the magma comes out at the seafloor, resulting in the addition of new materials to the oceanic crust.

This formation of new crust results in the expansion of the plates. The size of the plates becomes larger on both sides of the ridge. The rocks that are formed along the mid-oceanic ridges are the geologically the youngest rocks.