What is the concentration of K^+ ions in a 0.025 M K_2CO_3 solution, assuming complete dissociation?

• A. 0.025 M
• B. 0.075 M
• C. 0.050 M
• D. 0.0125 M

Answer: (C)

Verified step by step guidance

1. Identify the chemical formula of the compound: potassium carbonate is K_2CO_3, which means each formula unit contains 2 potassium ions (K^+) and 1 carbonate ion (CO_3^{2-}).
2. Write the dissociation equation for K_2CO_3 in water, assuming complete dissociation: K_2CO_3 \rightarrow 2K^+ + CO_3^{2-}.
3. Determine the molar concentration of K_2CO_3 given, which is 0.025 M. This means 0.025 moles of K_2CO_3 dissociate per liter of solution.
4. Calculate the concentration of K^+ ions by multiplying the concentration of K_2CO_3 by the number of K^+ ions produced per formula unit: [K^+] = 2 \times 0.025 \text{ M}.
5. Express the final concentration of K^+ ions in molarity, which will be twice the initial concentration of K_2CO_3 due to the 2:1 ratio in dissociation.