Question

Determine the concentration of CO3 that would be required to cause a precipitation to occur in a 3.0E-4 M solution of barium ions. The Ksp for BaCO3 is 5.1E-9.

Answer 1

Answer on Question #71703 - Chemistry - Other

Question:

Determine the concentration of CO3 that would be required to cause a precipitation to occur in a 3.0E-4 M solution of barium ions. The Ksp for BaCO3 is 5.1E-9.

Solution:

The reaction equation is the following:

$$CO_3^{2-} + Ba^{2+} \leftrightarrow BaCO_3 \downarrow$$

The equilibrium constant is the product of the equilibrium concentrations of carbonate anion and barium cation:

$$K_{sp} = [CO_3^{2-}] [Ba^{2+}]$$

Thus, if the product is higher than $K_{sp}$, the precipitation occurs. Let's calculate the concentration of carbonate anion in the equilibrium with $3.0 \cdot 10^{-4} \, \text{M}$ of barium cations:

$$[CO_3^{2-}] = \frac{K_{sp}}{[Ba^{2+}]} = \frac{5.1 \cdot 10^{-9}}{3.0 \cdot 10^{-4}} = 1.7 \cdot 10^{-5} \, \text{M}$$

Thus, the concentration of carbonate anion must be higher than $1.7 \cdot 10^{-5} \, \text{M}$ for the precipitation to occur.

Answer: The concentration of $CO_3^{2-}$ is required to be higher than $1.7 \cdot 10^{-5} \, \text{M}$ to cause a precipitation.

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