Although soluble barium compounds are

toxic, suspensions of insoluble barium sul-
fate are routinely swallowed for upper gas-
trointestinal X-ray studies. Why is barium
carbonate not used?
1. Stomachs contain HCl and all carbonates
dissolve in acid.2. Barium carbonate is too expensive.
3. Barium carbonate is soluble in plain wa-
ter.
4. All carbonates are toxic, whether soluble
or not.

1 answer

Big hint: BaSO4 doesn't dissolve in acids(actually it does a little but it is VERY little); BaCO3 does.