Molarity Calculation: Determining Chloride Anion Concentration

What is the final molarity of chloride anion in the solution after dissolving 6.17 g of zinc chloride in a 75.0 mM aqueous solution of potassium carbonate?

The concentration of chloride anion in the solution is calculated by determining the moles of chloride from the zinc chloride, then dividing by the volume of the solution. The molarity of the chloride anion in the final solution is 0.258 M.

Calculating Moles of Zinc Chloride

Firstly, we need to calculate the number of moles of zinc chloride (ZnCl2) that is added to the solution. The molar mass of ZnCl2 is about 136.286 g/mol. Therefore, the number of moles of ZnCl2 in 6.17 g is: 6.17 g / 136.286 g/mol = 0.0452 mol.

Determining Moles of Chloride Ion

When ZnCl2 dissolves, it dissociates into Zn2+ and 2Cl- ions. Therefore, the number of moles of chloride ion (Cl-) produced is 0.0452 mol * 2 = 0.0904 mol.

Calculating Final Molarity of Chloride Anion

Finally, to calculate the molarity of the chloride anion in the final solution, we divide the total moles of chloride ions by the total volume of the solution in liters: 0.0904 mol / 0.350 L = 0.258 M. Thus, the concentration of chloride ion is 0.258 M.
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