Which of the following is the correct chemical formula for aluminum carbonate?

• A. Al(CO3)3
• B. AlCO3
• C. Al3(CO3)2
• D. Al2(CO3)3

Answer: (D)

Verified step by step guidance

1. Identify the charges of the ions involved: aluminum typically forms a +3 charge (Al^{3+}), and the carbonate ion (CO_3) has a -2 charge (CO_3^{2-}).
2. To write the correct formula for aluminum carbonate, balance the total positive and negative charges so that the compound is electrically neutral.
3. Set up the charge balance equation: let the number of aluminum ions be x and the number of carbonate ions be y. Then, 3x (positive charges) must equal 2y (negative charges), or 3x = 2y.
4. Find the smallest whole number ratio that satisfies 3x = 2y. This ratio is x = 2 and y = 3, meaning 2 aluminum ions and 3 carbonate ions combine.
5. Write the chemical formula using the ratio found: Al_2(CO_3)_3, which shows 2 aluminum ions and 3 carbonate ions combined to form a neutral compound.