Calculate the pH of each of the following solutions. a. 0.12 M KNO 2 b. 0.45 M NaOCl c. 0.40 M NH 4 ClO 4

Interpretation: The pH value for each of the given solutions to be calculated.

Concept introduction: The pH of a solution is defined as a figure that expresses the acidity of the alkalinity of a given solution.

The pOH of a solution is calculated by the formula, pOH=−log[OH−]

The sum, pH+pOH=14

At equilibrium, the equilibrium constant expression is expressed by the formula,

Ka=Concentration of productsConcentration of reactants

The value of Kw is calculated by the formula,

Kw=Ka⋅Kb

To determine: The pH value for each of the given solution of 0.12 M KNO2 .

Explanation

The equilibrium constant expression for the given reaction is, Kb=[HNO2][OH−][NO2−]

The dominant equilibrium reaction is,

NO2−(aq)⇌HNO2(aq)+OH−(aq)

At equilibrium, the equilibrium constant expression is expressed by the formula,

Kb=Concentration of productsConcentration of reactants

Where,

• Kb is the base ionization constant.

The equilibrium constant expression for the given reaction is,

Kb=[HNO2][OH−][NO2−] (1)

The Kb value is 2.5×10-11_ .

The value, Kw=Ka⋅Kb

The value of Ka for HNO2 is 4.0×10−4 .

The value of Kb is calculated by the formula,

Kb=KwKa

Substitute the value of Ka in the above expression.

Kb=1.0×10−144.0×10−4=2.5×10-11_

The [OH−] is 1.73×10-6 M_ .

The change in concentration of NO2− is assumed to be x .

The liquid components do not affect the value of the rate constant.

The ICE table for the stated reaction is,

NO2−(aq)⇌HNO2(aq)+OH−(aq)Inititial concentration0.1200Change−x+x+xEquilibrium concentration0.12−xxx

The equilibrium concentration of [NO2−] is (0

Interpretation: The pH value for each of the given solutions to be calculated.

Concept introduction: The pH of a solution is defined as a figure that expresses the acidity of the alkalinity of a given solution.

The pOH of a solution is calculated by the formula, pOH=−log[OH−]

The sum, pH+pOH=14

At equilibrium, the equilibrium constant expression is expressed by the formula,

Ka=Concentration of productsConcentration of reactants

The value of Kw is calculated by the formula,

Kw=Ka⋅Kb

To determine: The pH value for each of the given solution of 0.45 M NaOCl .

Interpretation: The pH value for each of the given solutions to be calculated.

Concept introduction: The pH of a solution is defined as a figure that expresses the acidity of the alkalinity of a given solution.

The pOH of a solution is calculated by the formula, pOH=−log[OH−]

The sum, pH+pOH=14

At equilibrium, the equilibrium constant expression is expressed by the formula,

Ka=Concentration of productsConcentration of reactants

The value of Kw is calculated by the formula,

Kw=Ka⋅Kb

To determine: The pH value for each of the given solution of 0.40 M NH4ClO4 .