Equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate are mixed together. Will it lead to precipitation of copper iodate? (For cupric iodate Ksp = 7.4 × 10–8 ) ?

To determine whether mixing equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate will result in the precipitation of copper iodate, we need to analyze the solubility product constant (Ksp) of cupric iodate and the concentrations of the ions involved in the reaction.

Understanding the Reaction

When sodium iodate (NaIO3) and cupric chlorate (Cu(ClO3)2) are mixed, they dissociate in solution:

• NaIO3 → Na⁺ + IO3⁻
• Cu(ClO3)2 → Cu²⁺ + 2ClO3⁻

The relevant ions for the precipitation of copper iodate (Cu(IO3)2) are Cu²⁺ and IO3⁻. The precipitation reaction can be represented as:

Cu²⁺ + 2IO3⁻ ⇌ Cu(IO3)2 (s)

Calculating Ion Concentrations

Since we are mixing equal volumes of the two solutions, the concentration of each ion after mixing will be halved. The initial concentration of each solution is 0.002 M, so after mixing, the concentrations will be:

• [Cu²⁺] = 0.002 M / 2 = 0.001 M
• [IO3⁻] = 0.002 M / 2 = 0.001 M

Determining the Ion Product

Next, we need to calculate the ion product (Q) for the precipitation of copper iodate. The expression for the solubility product (Ksp) of copper iodate is given by:

Ksp = [Cu²⁺][IO3⁻]²

Substituting the concentrations we found:

Q = [Cu²⁺][IO3⁻]² = (0.001)(0.001)² = 0.001 × 0.000001 = 1 × 10⁻⁹

Comparing Q with Ksp

Now, we compare the calculated ion product (Q) with the Ksp value of copper iodate:

• Ksp = 7.4 × 10⁻⁸
• Q = 1 × 10⁻⁹

Since Q (1 × 10⁻⁹) is less than Ksp (7.4 × 10⁻⁸), the solution is not saturated with respect to copper iodate. This means that the conditions are not favorable for precipitation to occur.

Final Thoughts

In summary, mixing equal volumes of 0.002 M sodium iodate and cupric chlorate will not lead to the precipitation of copper iodate because the ion product is less than the solubility product constant. Therefore, the solution will remain clear without any solid precipitate forming.