Final answer:
In the mixed solution of CuCl₂ and AgNO₃, the NO₃− ion will have the highest concentration after the precipitation reaction goes to completion.
Step-by-step explanation:
To determine which ion will have the highest concentration in the mixed solution after mixing 25 mL of 0.40 M CuCl₂(aq) with 75 mL of 0.20 M AgNO₃(aq), and given the precipitation reaction goes to completion, let's first write the balanced equation for the reaction:
CuCl₂ (aq) + 2 AgNO3(aq) → Cu(NO3)₂ (aq) + 2 AgCl(s)
After mixing, the total volume of solution is 100 mL. The moles of CuCl₂ are calculated by multiplying its concentration (0.40 M) by its volume (0.025 L), resulting in 0.010 moles. Similarly, the moles of AgNO₃ are 0.20 M * 0.075 L = 0.015 moles.
When the two solutions mix, Ag+ ions will combine with Cl− ions to form AgCl(s), which precipitates from the solution. This means that Cl− ions will no longer be free in solution, and all 0.010 moles of Cl− will precipitate with an equivalent amount of Ag+, leaving 0.005 moles of Ag+ in solution. Since no copper precipitates and there are 0.010 moles of Cu2+, this cation will remain dissolved.
Therefore, the concentration of Cu2+ ions remains at 0.010 moles/0.1 L = 0.10 M. The final concentration of Ag+ after precipitation is 0.005 moles/0.1 L = 0.05 M. All the Cl− ions have precipitated, and finally, the nitrate ions (NO3−) were spectators and retain their initial concentration of 0.20 M * 0.075 L / 0.1 L = 0.15 M.
Thus, the ion with the highest concentration in the solution after the reaction is NO3− ion (D).