Explain why a common ion lowers the solubility of an ionic compound

From Le Chatelier's principle, that happens to the solubility of a slightly soluble ionic compound when a common ion is added and The solubility of a slightly soluble ionic compound decreases. MX ---> M+ + X-

If you now have some other ionic compound such as QX, this will dissociate to Q+ + X-

Here, the common ion is X. This will push the reaction of MX ---> M+ X- back to the left because of adding more X-. This results in decrease in solubility.

- both b and d.

-since b and d are the closest coastlines then that makes it the most affected.

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