How many OH⁻ ions are present in 3.00 mol of Ca(OH)₂?

• A. 3.61 × 10²⁴
• B. 3.61 × 10²⁴
• C. 1.81 × 10²⁴
• D. 3.61 × 10²³

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula and the number of hydroxide ions (OH⁻) per formula unit of calcium hydroxide, Ca(OH)₂. Each formula unit contains 2 OH⁻ ions.
2. Determine the total moles of OH⁻ ions by multiplying the moles of Ca(OH)₂ by the number of OH⁻ ions per formula unit: \(\text{moles of OH}^- = 3.00 \text{ mol Ca(OH)}_2 \times 2\).
3. Recall Avogadro's number, which is \$6.022 \times 10^{23}$ entities per mole, to convert moles of OH⁻ ions to the number of OH⁻ ions.
4. Calculate the total number of OH⁻ ions by multiplying the moles of OH⁻ ions by Avogadro's number: \(\text{number of OH}^- = \text{moles of OH}^- \times 6.022 \times 10^{23}\).
5. Express the final answer in scientific notation to match the given options.