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

• A. Ba_2(OH)
• B. Ba_2O_2H_2
• C. Ba(OH)_2
• D. BaOH

Answer: (C)

Verified step by step guidance

1. Understand that barium hydroxide is a compound formed from barium ions and hydroxide ions. Barium is an alkaline earth metal in group 2 of the periodic table, so it typically forms a 2+ charge as an ion: \(\mathrm{Ba^{2+}}\).
2. Recognize that the hydroxide ion, \(\mathrm{OH^-}\), carries a 1- charge. To balance the charges in the compound, the total positive charge must equal the total negative charge.
3. Since barium has a 2+ charge and hydroxide has a 1- charge, two hydroxide ions are needed to balance one barium ion. This leads to the formula \(\mathrm{Ba(OH)_2}\), where the subscript 2 applies to the hydroxide group.
4. Check the other options: \(\mathrm{Ba_2(OH)}\) suggests two barium atoms with one hydroxide, which does not balance charges; \(\mathrm{Ba_2O_2H_2}\) is a rearrangement of atoms but not the conventional formula; \(\mathrm{BaOH}\) implies one barium and one hydroxide, which does not balance charges.
5. Conclude that the correct chemical formula for barium hydroxide is \(\mathrm{Ba(OH)_2}\), reflecting the proper ratio of ions to achieve electrical neutrality.