If the concentration of sodium is greater outside a cell than inside then inside the cell, which process could move sodium out of the cell

Active transport requires energy when moving molecules against a concentration agent. It requires for specific membrane transport proteins. Only a certain type of protein can move a certain type of substance.

The three main types of Active Transport are:

1) Sodium-Potassium Pump

2) Endocytosis

3) Exocytosis