Question

which has the correct name - formula combination?
answer:
a barium sulfate - ba(so₄)₂
b calcium phosphate - ca₂(po₄)₃
c lithium sulfate - liso₄
d potassium phosphate - k₃po₄

Explanation:

Step1: Analyze barium sulfate formula

Barium ion \(Ba^{2 +}\), sulfate ion \(SO_{4}^{2 -}\). Using criss - cross method (charge of cation becomes subscript of anion and vice - versa, then reduce if possible), formula is \(BaSO_{4}\), not \(Ba(SO_{4})_{2}\).

Step2: Analyze calcium phosphate formula

Calcium ion \(Ca^{2+}\), phosphate ion \(PO_{4}^{3 -}\). Using criss - cross method, formula is \(Ca_{3}(PO_{4})_{2}\), not \(Ca_{2}(PO_{4})_{3}\).

Step3: Analyze lithium sulfate formula

Lithium ion \(Li^{+}\), sulfate ion \(SO_{4}^{2 -}\). Using criss - cross method, formula is \(Li_{2}SO_{4}\), not \(LiSO_{4}\).

Step4: Analyze potassium phosphate formula

Potassium ion \(K^{+}\), phosphate ion \(PO_{4}^{3 -}\). Using criss - cross method, formula is \(K_{3}PO_{4}\).

Answer:

D. potassium phosphate - \(K_{3}PO_{4}\)