A solution is prepared by dissolving 0.50 mol of NaCl in enough water to make 1.0 L of solution. What is the molarity of Cl⁻ in the solution?

• A. 0.50 M
• B. 2.0 M
• C. 0.25 M
• D. 1.0 M

Answer: (A)

Verified step by step guidance

1. Identify the solute and the ions it dissociates into. Sodium chloride (NaCl) dissociates completely in water into Na⁺ and Cl⁻ ions.
2. Write the dissociation equation: \(\text{NaCl} \rightarrow \text{Na}^+ + \text{Cl}^-\).
3. Determine the moles of Cl⁻ ions produced. Since 1 mole of NaCl produces 1 mole of Cl⁻, the moles of Cl⁻ will be equal to the moles of NaCl dissolved, which is 0.50 mol.
4. Calculate the molarity of Cl⁻ ions using the formula for molarity: \(M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}\).
5. Substitute the values: moles of Cl⁻ = 0.50 mol, volume = 1.0 L, so \(M_{Cl^-} = \frac{0.50}{1.0}\).