Mass-radius diagrams of exoplanets reveal a plethora of exotic worlds. Whether these worlds can support the emergence of life is hotly debated. An exotic world of particular importance is the ocean world. Some ocean worlds are likely so rich in water that they lack continents. I will present new ideas for the ocean-atmosphere chemical exchange, and the pH of these exotic oceans. I will talk about the emergence of life in diluted environments and the unique habitable zone of these worlds.