Calculate the solubility of BaSO₄ (a) in pure water and (b) in the presence of 0.010 M Ba(NO₃)₂. K_sp for BaSO₄ is 1.1 × 10⁻¹⁰.

Interpretation:

Solubility of salt BaSO4 has to be calculated in pure water.

Concept introduction:

The solubility of a salt is defined as the maximium amount of salt that can be dissolved in definite amount of solvent. It is expressed in moles per liter or grams per liter. Solubility in terms of moles per liter is called molar solubility and is defined as the number of moles of solute (salt) dissolved in per liter of solution.

Solubility product constant Ksp is an equilibrium constant and is defined as the product of the equilibrium concentration of the ions of the salt raised to the power of their coefficients in the balanced chemical equation.

Expression for Ksp of a salt is given as,

AxBy(s)⇌xAy+(aq)+yB−x(aq)Ksp=[Ay+]x[B−x]y

Relation between Ksp and s is derived as follows,

EquationAxBy⇌xAy++yB−xInitial(M)00Change(M)+xs+ysEquilibrium(M)xsys

Ksp=[Ay+]x[B−x]yKsp=(xs)x(ys)y=xxyy(s)x+y

Rearrange the expression for s.

(s)x+y=Kspxxyy=(Kspxxyy)1/(x+y)

Here,

• x is the coefficient of cation A+y
• y is the coefficient of anion B−x
• s is the molar solubility

Ksp is calculated by using molar solubility of the salt.

Solubility of salt BaSO4 in pure water is to be calculated as follows,

Given:

The value of solubility product Ksp of BaSO4 is 1.1×10−10.

BaSO4 when dissolved in water dissociates as ,

BaSO4(s)⇌ Ba2+(aq) + SO42−(aq)

The ICE table is as follows,

EquationBaSO4⇌Ba2++SO42−Initial (M)00Change (M)+s+sEquilibrium (M) s s

Ksp =

Interpretation:

The solubility of BaSO4 in the presence of 0.010 M  Ba(NO3)2 has to be calculated.

Concept introduction:

The solubility of a salt is defined as the maximium amount of salt that can be dissolved in definite amount of solvent. It is expressed in moles per liter or grams per liter. Solubility in terms of moles per liter is called molar solubility and is defined as the number of moles of solute (salt) dissolved in per liter of solution.

Solubility product constant Ksp is an equilibrium constant and is defined as the product of the equilibrium concentration of the ions of the salt raised to the power of their coefficients in the balanced chemical equation.

Expression for Ksp of a salt is given as,

AxBy(s)⇌xAy+(aq)+yB−x(aq)Ksp=[Ay+]x[B−x]y

Relation between Ksp and s is derived as follows,

EquationAxBy⇌xAy++yB−xInitial(M)00Change(M)+xs+ysEquilibrium(M)xsys

Ksp=[Ay+]x[B−x]yKsp=(xs)x(ys)y=xxyy(s)x+y

Rearrange the expression for s.

(s)x+y=Kspxxyy=(Kspxxyy)1/(x+y)

Here,

• x is the coefficient of cation A+y
• y is the coefficient of anion B−x
• s is the molar solubility

Ksp is calculated by using molar solubility of the salt.