Ocean worlds are those planetary bodies that contain or have contained for a long period of time significant amounts of liquid water, either at the surface and/or in the subsurface. In our solar system, besides the Earth, both Ceres and the main icy moons of the outer solar system (OSS) show evidence of fulfilling or having fulfilled this condition. The maintenance of an ocean requires a constant energetic input over time to prevent solidification to ice. In those bodies with a predominantly rocky layer, such as the Earth and to a lesser extent Ceres, this input comes from radioactive decay, in addition to the primordial heat after its formation. However, in the icy moons of the OSS, farther from the Sun, this input comes from the strong tidal forces produced during their orbit around their larger parent planets, i.e., the gas or icy giants. This energetic input also favors other substances (such as gases, salts, and silicates), to be released from the more rocky layers (usually located below the hydrospheres or partially intermixed) and interact with the water molecules. In this talk my intention is to show the aqueous chemistry, and the geological implications, that can take place on the ocean worlds of the OSS. I will show how water chemistry evolves from the interior to the surface due to pressure and temperature changes. The evolution of cryomagmas, according to their initial composition and depending on what they encounter on their way, will give rise to various chemical reactions and precipitation of different minerals. Moreover, when they reach the surface, the radical environmental change causes the cryomagmas to continue to modify themselves chemically and physically. Experimental study and geochemical and geophysical modeling of the various processes that cryomagmas can follow from the interior to the surface serve to infer the interior composition from data taken at the surface during space missions to these planetary bodies.