Which of the following barium salts is insoluble in water?

• A. Barium nitrate (Ba(NO_3)_2)
• B. Barium sulfate (BaSO_4)
• C. Barium chloride (BaCl_2)
• D. Barium acetate (Ba(C_2H_3O_2)_2)

Answer: (B)

Verified step by step guidance

1. Recall the general solubility rules for ionic compounds in water, which help predict whether a salt will dissolve or remain solid.
2. Note that most nitrate (NO\_3\^-) salts are soluble in water without exception, so barium nitrate (Ba(NO\_3\)_2) is soluble.
3. Recognize that most chloride (Cl\^-) salts are soluble, except those of silver, lead, and mercury, so barium chloride (BaCl\_2) is soluble.
4. Understand that most acetate (C\_2H\_3O\_2\^-) salts are soluble, so barium acetate (Ba(C\_2H\_3O\_2)\_2) is soluble.
5. Recall that sulfate (SO\_4\^2\-) salts are generally soluble, but barium sulfate (BaSO\_4) is a well-known exception and is insoluble in water.