Calculate the [OH^–] of each of the following solutions at 25°C. Identify each solution as neutral, acidic, or basic.

  a. [H⁺] = 1.0 × 10^–7 M

  b. [H⁺] = 8.3 × 10^–16 M

  c. [H⁺] = 12 M

  d. [H⁺] = 5.4 × 10^–5 M

  46. Calculate the [H⁺] of each of the following solutions at 25°C. Identify each solution as neutral, acidic, or basic.

  a. [OH^–] = 1.5 M

  b. [OH^–] = 3.6 × 10^–15 M

  c. [OH^–] = 1.0 × 10^–7 M

  d. [OH^–] = 7.3 × 10^–4 M

  49. Calculate the pH and pOH of the solutions in Exercises 45 and 46.

Interpretation:

The pH and the pOH values for thesolution in Exercises 45 and 46 are to be calculated.

Concept introduction:

The pH of a solution is define as a figure that expresses the acidity of the alkalinity of a given solution. A logarithmic scale is used on which, the value 7 corresponds to a neutral species, a value less than 7 corresponds to an acid and a value greater than 7 corresponds to a base.

The pOH of a solution is the measure of the [OH−] .

The pH of a solution is calculated by the formula, pH=−log[H+]

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

At 25 °C , pH+pOH=14

Explanation

(45a)

Calculation of pH of the solution

The pH value is 7_ .

Given

The temperature is 25 °C .

The [H+]=1.0×10−7 M .

The pH of a solution is calculated by the formula,

pH=−log[H+]

Substitute the given value of [H+] in the above expression.

pH=−log[1.0×10−7]=7_

Calculation of pOH of the solution

The pOH value is 7_ .

At 25 °C ,

pH+pOH=14

Substitute the calculated value of pH in the above expression.

pH+pOH=147+pOH=14pOH=7_

(45b)

Calculation of pH of the solution

The pH value is 15_ .

Given

The temperature is 25 °C .

The [H+]=8.3×10−16 M .

The pH of a solution is calculated by the formula,

pH=−log[H+]

Substitute the given value of [H+] in the above expression.

pH=−log[8.3×10−16]=15_

Calculation of pOH of the solution

The pOH value is -1_ .

At 25 °C ,

pH+pOH=14

Substitute the calculated value of pH in the above expression.

pH+pOH=1515+pOH=14pOH=-1_

(45c)

The pH value is 1.1_ .

Given

The temperature is 25 °C .

The [H+]=12 M .

The pH of a solution is calculated by the formula,

pH=−log[H+]

Substitute the given value of [H+] in the above expression.

pH=−log[12]≈1.1_

The pOH value is 12.9_ .

At 25 °C ,

pH+pOH=14

Substitute the calculated value of pH in the above expression.

pH+pOH=1.11.1+pOH=14pOH=12.9_

(45d)

The pH value is 4.3_ .

Given

The temperature is 25 °C .

The [H+]=5.4×10−5 M .

The pH of a solution is calculated by the formula,

pH=−log[H+]

Substitute the given value of [H+] in the above expression.

pH=−log[5.4×10−5]≈4.3_

The pOH value is 9.7_ .

At 25 °C ,

pH+pOH=14

Substitute the calculated value of pH in the above expression.

pH+pOH=4.34.3+pOH=14pOH=9.7_

(46a)

The pOH value is 0