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.
Big hint: BaSO4 doesn't dissolve in acids(actually it does a little but it is VERY little); BaCO3 does.
To determine why barium carbonate is not used for upper gastrointestinal X-ray studies, we can analyze each of the given options.
1. Stomachs contain HCl and all carbonates dissolve in acid.
Carbonates, including barium carbonate, do indeed dissolve in acid. However, it's important to note that during upper gastrointestinal X-ray studies, a suspension of the barium compound is used, not a solution. In a suspension, the solid particles are dispersed and remain insoluble, even in the presence of acid. Therefore, this option is not the correct answer.
2. Barium carbonate is too expensive.
The price of a substance is not a determining factor when considering its use for medical purposes. Therefore, this option is unlikely correct.
3. Barium carbonate is soluble in plain water.
If barium carbonate were soluble in water, it would not be suitable for use in upper gastrointestinal X-ray studies. The purpose of using a barium compound is to provide a contrast agent that remains insoluble to get clear X-ray images. This option suggests that barium carbonate is soluble, which is incorrect.
4. All carbonates are toxic, whether soluble or not.
While it is true that some carbonates can be toxic, whether they are soluble or insoluble, this is not the reason why barium carbonate is not used for X-ray studies. The toxicity of barium carbonate is not the primary concern when determining its use in this context.
Therefore, the correct answer is option 3: Barium carbonate is soluble in plain water. However, it is important to note that the given statement is incorrect. Barium carbonate is insoluble in water, which makes it unsuitable for upper gastrointestinal X-ray studies where a contrast agent is required. The correct compound that is routinely used for this purpose is barium sulfate, as it remains insoluble in the stomach and provides the necessary contrast for X-ray imaging.