Why is barium hydroxide preferred for detecting CO2 and in titrations?

[meawinner]

I have this question to do for homework and i can't find the answer anywhere so please can someone help me. Barium hydroxide can sometimes be used instead of limewater to detect small quantities of CO2. Why is Barium hydroxide preferred here and in using it instead of sodium hydroxide for titrations where it is important to exclude dissolved carbonate ions? Please help. Thank-you

 

[GCT]

BaOH reacts with the acidic oxide, the carbon dioxide, to form a salt and water; and thus CO2 is gotten rid of this way. Also barium carbonate is an insoluble substance in water; thus by having barium metals we can effectively precipitate the carbonate.

 

[thunderfvck]

I think you mean Ba(OH)2?
What does barium carbonate look like?
I looked it up on chemfinder and it shows me the carbonate molecule and the barium ion, which is what it dissociates into I guess. But not in water since it's an insoluble salt, well maybe just a tiny bit but whatever. But the solid form of barium carbonate must have some kind of structure other than the carbonate and barium ions. I guess barium forms a four-sided ring with the two oxygens, or what?
help.
help help...