is CA(SO4)2 an acid or base

Question

anonymous · Answer

It is neither an acid, nor a base. It's a salt. I assume the question you're asking is about the pH of its solution. CaSO4 is a salt produced from Ca(OH)2 and H2SO4. The former is a weak base, whereas the sulfuric acid is a strong mineral acid, therefore, the aqueous solution of CaSO4 is somewhat acidic.

adamconner · Answer

well how am I supposed to know its produced from these Ca(OH)2 and H2SO4. and that it won't break up into Ca 2+ and SO4 2-. then SO4 2- + h2o=hso4- + OH- ?

anonymous · Answer

So, first, a salt is the product of an acid and a base. In this case, calcium can only form bases, while the sulphate group can be a part of an acid. 

The breakup you're talking about is dissociation in water. It happens to ionic compounds when they interact with water molecules. This produces the ions Ca 2+ and SO4 2-. However, as calcium hydroxide is not highly soluble in water, some precipitate falls, according to the equation:
$$H _{2}O \rightarrow H ^{+}+OH ^{-}$$
$$Ca ^{2+} + 2OH ^{-} \rightarrow Ca(OH)_{2}$$
Sulfate ions are highly soluble in water, that's why the reaction you suggested that produces HSO4, will occur to a negligible extent. They practically stay as they are. 

All of this results in the balance of hydrogen and hydroxide ions disrupted. Some of the OH are precipitated, that's why the concentration of hydrogen ions is larger, so pH < 7. The solution is acidic.

Do you need further details?

adamconner · Answer

ahaaa. I got it!

adamconner · Answer

can you help me with my question?

anonymous · Answer

you're brilliant, thank you infinitely!

anonymous · Answer

You're welcome! @bayleybeee