What is the concentration of Cl⁻ ions in a 0.1 M solution of calcium chloride (CaCl₂)?

• A. 0.1 M
• B. 0.05 M
• C. 0.01 M
• D. 0.2 M

Answer: (D)

Verified step by step guidance

1. Identify the chemical formula of calcium chloride, which is CaCl\_2. This means each formula unit dissociates into one Ca\^{2+} ion and two Cl\^{-} ions in solution.
2. Write the dissociation equation for calcium chloride in water: CaCl\_2 (aq) \rightarrow Ca\^{2+} (aq) + 2 Cl\^{-} (aq).
3. Recognize that the concentration of CaCl\_2 given is 0.1 M, which means 0.1 moles of CaCl\_2 dissolve per liter of solution.
4. Since each mole of CaCl\_2 produces 2 moles of Cl\^{-} ions, multiply the concentration of CaCl\_2 by 2 to find the concentration of Cl\^{-} ions: \([Cl\^{-}] = 2 \times 0.1 \text{ M}\).
5. Calculate the concentration of Cl\^{-} ions using the multiplication from the previous step to find the final concentration in molarity.