Answer: BaI
{2}
⋅
4
H
{2}
O
any number in {} is small
Explanation: The idea here is that you need to use the number of moles of anhydrous barium iodide, BaI
{2}
, and of water, H {2} O
, to find the mole ratio that exists between the anhydrous salt and its water of hydration in the hydrate.
