Calculating Molarity of Cl- Ions in a Solution: A Detailed Guide

Understanding the Problem

To find the molarity of chloride (Cl-) ions when 0.2 moles of NaCl and 0.2 moles of BaCl2 are dissolved in a 500 mL solution, we need to first determine how many Cl- ions are contributed by each compound. This requires an understanding of the dissociation of ionic compounds in solution.

Solving the Problem

The dissociation process in a solution is a fundamental concept in solution chemistry. Let's break it down step by step.

Dissociation of NaCl

- Sodium chloride (NaCl) dissociates into sodium (Na ) and chloride (Cl-) ions.

- Therefore, 0.2 moles of NaCl will produce 0.2 moles of Cl- ions.

Dissociation of BaCl2

- Barium chloride (BaCl2) dissociates into barium (Ba2 ) and two chloride (2 Cl-) ions.

- Therefore, 0.2 moles of BaCl2 will produce 0.2 × 2 0.4 moles of Cl- ions.

Total moles of Cl- ions:

- From NaCl: 0.2 moles

- From BaCl2: 0.4 moles

- Total Cl- ions 0.2 0.4 0.6 moles

Calculating Molarity

Molarity (M) is calculated using the formula:

M moles of solute / volume of solution in liters

The volume of the solution is 500 mL, which is equivalent to 0.5 L.

Therefore, the molarity of Cl- ions is:

Molarity of Cl- 0.6 moles / 0.5 L 1.2 M

Conclusion: The molarity of Cl- ions in the solution is 1.2 M.

Further Explanation

To further understand the concept, let's revisit the steps:

Dissociation of NaCl: Each mole of NaCl produces one mole of Cl- ions. Dissociation of BaCl2: Each mole of BaCl2 produces two moles of Cl- ions. Total moles of Cl- ions: Adding the moles of Cl- ions from both compounds. Molarity calculation: Dividing the total moles of Cl- ions by the volume of the solution in liters.

By following these steps, we can accurately calculate the molarity of Cl- ions in any given solution.

Conclusion

Understanding the dissociation process and applying the molarity formula are crucial for solving such problems. The detailed breakdown and calculation above should help you grasp the concepts thoroughly.

Additional Resources

- Dissociation of Compounds in Solution
- Molarity Formula Calculator
- Solution Chemistry Tutorial