# Could a safe water ocean exist on a world with predominantly chlorine atmosphere?

I am researching for a Si-Fi book. Would a water ocean on a world with a predominantly chlorine ($\ce{Cl2}$) atmosphere be safe to touch? Would the chlorine over time saturate the water creating a "laundry bleach' solution, or would it create a ocean of hydrocloric acid ($\ce{HCl}$) and hypoclorous acid ($\ce{HOCl}$), or would the chlorine just not react with the water that much?

## 1 Answer

Chlorine gas is dissolved in drinking water at low concentrations for disinfection purposes. Chlorine gas has also be dissolved in somewhat higher concentrations in swimming pools.

The amount of chlorine dissolved will strongly depend upon pressure. If the atmospheric pressure on the planet is low the concentration of chlorine gas in the water will be low.

Yes, most of the dissolved chlorine will reversibly react to form HCl and HOCl.

For quantitative information about the equilibrium constant and solubility as a function of pressure and temperature see Solubility of Chlorine in Water Industrial and Engineering Chemistry vol. 33, pages 741–744.

• DavePhD. Thank you, That is exactly what I needed to know. I think for the situation in the book the water will be considered safe to touch and use as a disinfectant but probably too Chlorinated to drink without processing. – Steve Jan 14 '16 at 16:27