The values of for and are and respectively at . If a mixture of these two solid salts is washed with — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

For simultaneous solubility, let the solubility of $CaCO_3$ be $x$ and $CaC_2O_4$ be $y$. Then $[Ca^{2+}] = x + y$, $[CO_3^{2-}] = x$, and $[C_2O_4^{2-}] = y$. The equations are $x(x+y) = 4.7 \times 10^{-9}$ and $y(x+y) = 1.3 \times 10^{-9}$. Adding them gives $(x+y)^2 = 6.0 \times 10^{-9} = 60 \times 10^{-10}$. Taking the square root, $[Ca^{2+}] = x+y = \sqrt{60} \times 10^{-5} \approx 7.746 \times 10^{-5} \text{ M}$.