Question

In the general formula for a hydrate, salt.XH20, what does the X represent?

Answer 1

So,

In the general formula for a hydrate:

$\text{salt}\mathrm{}XH_2O$

"X" represents the number of moles of water present as hydrate in the salt.

For example, copper sulfate pentahydrate means x = 5 moles of water present as a hydrate.