# Solubility of a salt of strong acid and strong base in pure water

Let us consider a salt of this type as AgCl. Let the solubility of the salt be

*s*mol/L. Such salt do not hydrolyze.Knowing the solubility product, solubility

*s*of AgCl can be calculated.# Solubility of a salt of strong acid and strong base in presence of a common ion (incapable of forming complex)

Let us calculate the solubility of AgCl in 0.1 M AgNO

_{3}solution.AgCl(s) î‚ƒ Ag

^{+ }_{(aq)}+ Cl^{â€“ }_{(aq)}AgNO

_{3 }â†’ Ag^{+}+ NO_{3 }^{â€“}Let the solubility of AgCl in the presence of 0.1 M AgNO

_{3}be*s*â€˜ mol/L. Then*s*â€˜ can be ignored with respect to 0.1 M. Therefore,

(0.1 +

*s*â€˜) = 0.1âˆ´

*s*â€˜ can be calculated provided we know

*K*

_{SP}of AgCl. It can be noticed that

*s*â€˜ would be less than

*s*.

# Solubility of a salt of strong acid and strong base in a solvent capable of forming complex

Let us consider the solubility of AgCl in

*c*M NH_{3}(as solvent). Let the solubility of AgCl in ammonia be*s"*mol/L, and*x*mol/L is the amount of salt-forming complex.where

*K*is the equilibrium constant for the formation of complex ion/species and is called the formation constant._{f}*K*values of complex formation are very high, so almost entire amount of Ag

_{f}^{+}would be converted into complex. This means that the value of

*x*approaches

*s"*. Thus (

*s"*â€“

*x*) would be very small. Let this small value be

*y*. Also the value of

*x*is small, so 2

*x*can be ignored with respect to

*c*. Therefore,

(

*c*â€“ 2*x*)*c*âˆ´

*K*_{SP}=*y*Ã—*s"*;Knowing the values of

*K*_{SP},*K*, and_{f}*c*, we can calculate the value of*s"*and*x*. It can notice that*s"*would be greater than*s*. Thus, complex formation increases the solubility of a salt.# Solubility of a salt of weak acid and strong base in pure water

Let the salt of this type be CH

_{3}COOAg and its solubility be*s*mol/L. Such salts undergo hydrolysis. Out of CH_{3}COO^{â€“}and Ag^{+}ions, CH_{3}COO^{â€“}ion will get hydrolyzed.Let the amount of CH

_{3}COO^{â€“}ion getting hydrolyzed be*x*mol/L.*K*

_{SP}= (

*s*â€“

*x*) Ã— (

*s*)

Solving these two equations, we get the values for

*s*and*x*.# Solubility of a salt of weak acid and strong base in acidic buffer

Let the solubility of CH

_{3}COOAg be*s'*mol/L in acidic buffer. Now, in the presence of free H^{+}(from acidic buffer), the anion of weak acid will form weak acid at equilibrium, but [H^{+}] in a buffer will remain constant.âˆ´

*K*_{SP}= (*s'*â€“*x'*) Ã— (*s'*)Knowing the values of

*K*_{SP},*K*_{a}, and the concentration of H^{+}ions in the buffer, we can calculate*s'*and x'. The value of*s'*would be greater than*s*. This implies that the solubility of a salt of weak acid and strong base is more in acidic buffer than in pure water.# Simultaneous solubility of two or more sparingly soluble salts

Simultaneous solubility means the solubility of a sparingly soluble salt in the presence of another sparingly soluble salt having a common ion. Let us assume the simultaneous solubilities of AgCl and AgBr in a solution are

*x*and*y*mol/L, respectively.;

*K*_{SP}= [Ag^{+}]_{total}Ã— [Cl^{â€“}];

*K*_{SP}= [Ag^{+}]_{total}Ã— [Br^{â€“}]*K*

_{SP}of AgCl = (

*x*+

*y*) Ã—

*x*

*K*

_{SP}of AgBr = (

*x*+

*y*) Ã—

*y*

From the above two expressions, we can calculate the simultaneous solubilities of AgCl and AgBr.