THE COMMON-ION EFFECT - I
{"Image DocumentName": "THE COMMON-ION EFFECT - I", "Image ImageDescription": "Calcite solubility is governed by the reaction: CaCO3(s) \uf0ab Ca2+ + CO32- (1) Suppose we added a second compound containing carbonate, and this compound is more soluble than calcite, e.g., Na2CO3. This compound will dissolve according to: Na2CO3(s) \uf0ab 2Na+ + CO32- (2) To the extent that reaction (2) proceeds to the right, by Le Chatlier\u2019s principle, this will force reaction (1) to the left, precipitating calcite. According to Le Chatlier\u2019s principle, any increase in the concentration of CO32- will shift the following reaction to the left and cause calcite to precipitate: CaCO3(s) \uf0ab Ca2+ + CO32- One way to increase the concentration of CO32- is to add a salt to the solution that both contains carbonate ion, and is more soluble than calcite. For example, Na2CO3 is much more soluble than calcite. Thus, when we add this salt to a solution saturated with calcite, its addition will cause CO32- to increase and therefore, calcite will precipitate. This is called the common-ion effect. The anion CO32- is the common-ion between CaCO3 and Na2CO3.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}