If two identical water mixable molecules that does not exist anywhere else on this planet is thrown into the ocean, what is the speed of the entropic diffision and what is the time it takes for them to reach thermodynamic equilibrium.

These two molecules will reach their average distance really fast, and the average distance is the median of probabilty between the farest and shortest distances these molecules can be away from eachother. Ignoring depth we will just say its a quarter of the circumference of earth 10 000Km.