I hate studying for my chemical practicals when I was in my secondary school. I don't understand why teachers made students do test tube experiments guessing what are those unknown compounds. Not knowing the value behind conducting these chemical experiments is  one thing and another thing is about memorizing the solubility of different compounds are some of the things I hate when I study for my practicals. Anyway, without fail, I screwed up every practicals because I have no interest in it and don't know why I am doing these experiments.

However, I learned that solubility of compounds is important recently. I remembered in chemistry, barium has a special property whereby some of its compounds are soluble while the others are not. Actually, there is an application in our daily life.

Doctors gave patients food mixed with barium sulfate (BaSO4) before taking x-rays of the digestive system. X-rays are good at looking hard objects like bones but not soft objects like tissues. Therefore, patients have to eat those food mixed with barium sulfate beforehand because barium helps in absorbing these x-rays which helps doctors in observing your digestive system.

Now, you know that barium sulfate is safe to be consumed or else doctors won't be giving you that. However, there is a case in Mansfield, Texas where Marie Robards poisons her father with barium acetate from school chemistry lab. Now, the question is why barium sulfate is consumable and not barium acetate?

This has to do with solubility of barium compounds. Barium sulfate used by doctors is insoluble and therefore, will not be absorbed in our body but barium acetate is. As barium acetate is soluble, it is absorbed into our bloodstream and the last thing we know is we are poisoned.

Therefore, it seems that solubility does matter and it can become a matter of life and death.