01:160:162 Lecture Notes - Lecture 23: Solubility Equilibrium, Ionic Compound, Rice Chart

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25 Jul 2017

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Dissolution of a sparingly soluble ionic compounds is an equilibrium process and extent of dissolution can be quantified by an equilibrium constant (the solubility-product constant ksp) Mathematical relationship between compound"s molar solubility (s) and its ksp depends on compound"s dissociation stoichiometry. If ksp is known, ice table can be used to determine molar solubility of a compound in water. Solubility of sparingly soluble compound will be decreased if solution already contains a common ion. When ionic compound is added to a solution that already contains the cation / anion of ionic compound, compound will dissociate less and be less soluble. Compare solubility of caf2 in water vs. caf2 in 1. 0 m naf (aq) (cid:1544) Because naf contains common ion to caf2 (cid:1543) caf2 does not dissociate as much and solubility is lower. Le chatelier: presence of f from naf disrupts the solubility of caf2. Solubility equilibrium does not go as much to the right as it does in pure water.

Related Questions

Common Ion Effect

A) Mg(OH)2 is a sparingly soluble compound, in this case a base, with a solubility product, Ksp, of 5.61Ã10â11. It is used to control the pH and provide nutrients in the biological (microbial) treatment of municipal wastewater streams.

Based on the given value of the Ksp, what is the molar solubility of Mg(OH)2 in pure H2O?

Express your answer with the appropriate units.

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molar solubility =

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The common-ion effect and solubility

The solubility of a slightly soluble compound can be greatly affected by the addition of a soluble compound with a common ion, that is, with one of the ions in the added soluble compound being identical to one of the ions of the slightly soluble compound. The general result of the addition of the common ion is to greatly reduce the solubility of the slightly soluble compound. In other words, the addition of the common ion results in a shift in the equilibrium of the slightly soluble compound.

Part B - Calculate the molar solubility in NaOH

Based on the given value of the Ksp, what is the molar solubility of Mg(OH)2 in 0.200 M NaOH?

Express your answer with the appropriate units.

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molar solubility =

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Part C

This question will be shown after you complete previous question(s).

The common-ion effect and buffer systems

A buffer is a mixed solution of a weak acid or base, combined with its conjugate. Note that this can be understood essentially as a common-ion problem: The conjugate is a common ion added to an equilibrium system of a weak acid or base. The addition of the conjugate shifts the equilibrium of the system to relieve the stress of the added concentration of the common ion. In a solution consisting of a weak acid or base, the equilibrium shift also results in a pH shift of the system.

It is the presence of the common ion in the system that results in buffering behavior, because both added H+ or OHâ ions can be neutralized.

Part D

What is the pH change of a 0.290 M solution of citric acid (pKa=4.77) if citrate is added to a concentration of 0.145 M with no change in volume?

Express the difference in pH numerically to two decimal places.

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Determine the molar amounts of Pb+2 and Cl-

use the values of this handout

Lead thiocyanate, Pb(SCN)2, has a Ksp value of 2.00Ã10?5. Part A Part complete Calculate the molar solubility of lead thiocyanate in pure water. The molar solubility is the maximum amount of lead thiocyanate the solution can hold. Express your answer with the appropriate units. View Available Hint(s)

1.71Ã10?2 M Previous Answers Correct

Common-Ion Effect Consider the dissolution of AB(s) : AB(s)?A+(aq)+B?(aq) Le ChÃ¢telier's principle tells us that an increase in either [A+] or [B?] will shift this equilibrium to the left, reducing the solubility of AB. In other words, AB is more soluble in pure water than in a solution that already contains A+ or B? ions. This is an example of the common-ion effect.

Part B Calculate the molar solubility of lead thiocyanate in 0.900 M KSCN. Express your answer with the appropriate units. View Available Hint(s) 8{\cdot}10^{-6} M

01:160:162 Lecture Notes - Lecture 23: Solubility Equilibrium, Ionic Compound, Rice Chart

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