Question

Question #b1cb9

Answer 1

Do you mean calcium oxide and water, by any chance?

Explanation:

I don't think that calcium oxide, `"CaO"`, reacts with hydrogen gas, `"H"_2`, so I'm going to assume that you want to know about the reaction between calcium oxide and water, `"H"_2"O"`.

Calcium oxide, also called quicklime, will react with water to form calcium hydroxide, `"Ca"("OH")_2`, also called slacked lime.

`"CaO"_ ((s)) + "H"_ 2"O"_ ((l)) -> "Ca"("OH")_ (2(s))`

Calcium hydroxide is relatively soluble in water, but the amount that does dissolve dissociates completely to produce a basic solution of `"pH" ~~ 12`.

It's worth mentioning that this reaction is quite exothermic, meaning that heat is being given off as calcium hydroxide is produced by the reaction.