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

• A. Al_2O_3
• B. AlOH
• C. Al(OH)_3
• D. Al_2(OH)_3

Answer: (C)

Verified step by step guidance

1. Identify the ions involved: aluminum typically forms a +3 charge ion (Al^{3+}), and the hydroxide ion (OH^-) has a -1 charge.
2. Determine the ratio of ions needed to balance the overall charge to zero. Since aluminum has a +3 charge, you need three hydroxide ions, each with a -1 charge, to balance it.
3. Write the chemical formula by placing the aluminum ion first, followed by the hydroxide ion in parentheses with a subscript indicating the number of hydroxide ions needed to balance the charge.
4. The correct formula is therefore Al(OH)_3, indicating one aluminum ion combined with three hydroxide ions.
5. Verify that the formula is electrically neutral by confirming that the total positive charge (+3) equals the total negative charge (3 × -1 = -3).