. Calculate the [H⁺] in each of the following solutions, and indicate whether the solution is acidic, basic, or neutral.

a. [ OH - ] = 7.86 × 10 − 4 M b. [ OH - ] = 5.44 × 10 − 8 M c. [ OH - ] = 3.19 × 10 − 3 M

d. [ OH - ] = 2.51 × 10 − 9 M

(a)

Interpretation:

The concentration of hydrogen ion [H+] should be calculated. If the solution is acidic, neutral or basic should be indicated.

Concept Introduction:

The concentration of hydrogen ions in a solution determines the acidity of a solution. If concentration of hydrogen ion is more than the solution is more acetic, if it is low, solution is less acidic.

The pH of solution is defined as negative log of hydrogen ion concentration thus, it can be calculated as follows:

pH=−log[H+]

Here, [H+] is concentration of hydrogen ion.

Similarly, pOH of a solution is defined as negative log of hydroxide ion concentration thus, it can be calculated as follows:

pOH=−log[OH−]

Here, [OH−] is concentration of hydroxide ion.

pH and pOH of a solution are related to each other as follows:

pH+pOH=14

In a pH scale, if the value of pH is below 7 the solution is said to be acidic in nature, if the Ph value is above 7 it is said to be basic in nature. At pH 7, the solution is neutral.

Given Information:

The concentration of hydroxide ion is 7.86×10−4 M

Calculation:

From the given hydroxide ion concentration, pOH of solution can be calculated as follows:

pOH=−log[OH−]

Putting the values,

pOH=−log(7.86×10−4)=3.10

From the pOH, pH of solution can be calculated as follows:

pH=14−pOH

Putting the value,

pH=14−3

(b)

Interpretation:

The concentration of hydrogen ion [H+] should be calculated. If the solution is acidic, neutral or basic should be indicated.

Concept Introduction:

The concentration of hydrogen ions in a solution determines the acidity of a solution. If concentration of hydrogen ion is more than the solution is more acetic, if it is low, solution is less acidic.

The pH of solution is defined as negative log of hydrogen ion concentration thus, it can be calculated as follows:

pH=−log[H+]

Here, [H+] is concentration of hydrogen ion.

Similarly, pOH of a solution is defined as negative log of hydroxide ion concentration thus, it can be calculated as follows:

pOH=−log[OH−]

Here, [OH−] is concentration of hydroxide ion.

pH and pOH of a solution are related to each other as follows:

pH+pOH=14

In a pH scale, if the value of pH is below 7 the solution is said to be acidic in nature, if the Ph value is above 7 it is said to be basic in nature. At pH 7, the solution is neutral.

(c)

Interpretation:

The concentration of hydrogen ion [H+] should be calculated. If the solution is acidic, neutral or basic should be indicated.

Concept Introduction:

The concentration of hydrogen ions in a solution determines the acidity of a solution. If concentration of hydrogen ion is more than the solution is more acetic, if it is low, solution is less acidic.

The pH of solution is defined as negative log of hydrogen ion concentration thus, it can be calculated as follows:

pH=−log[H+]

Here, [H+] is concentration of hydrogen ion.

Similarly, pOH of a solution is defined as negative log of hydroxide ion concentration thus, it can be calculated as follows:

pOH=−log[OH−]

Here, [OH−] is concentration of hydroxide ion.

pH and pOH of a solution are related to each other as follows:

pH+pOH=14

In a pH scale, if the value of pH is below 7 the solution is said to be acidic in nature, if the Ph value is above 7 it is said to be basic in nature. At pH 7, the solution is neutral.

(d)

Interpretation:

The concentration of hydrogen ion [H+] should be calculated. If the solution is acidic, neutral or basic should be indicated.

Concept Introduction:

The concentration of hydrogen ions in a solution determines the acidity of a solution. If concentration of hydrogen ion is more than the solution is more acetic, if it is low, solution is less acidic.

The pH of solution is defined as negative log of hydrogen ion concentration thus, it can be calculated as follows:

pH=−log[H+]

Here, [H+] is concentration of hydrogen ion.

Similarly, pOH of a solution is defined as negative log of hydroxide ion concentration thus, it can be calculated as follows:

pOH=−log[OH−]

Here, [OH−] is concentration of hydroxide ion.

pH and pOH of a solution are related to each other as follows:

pH+pOH=14

In a pH scale, if the value of pH is below 7 the solution is said to be acidic in nature, if the Ph value is above 7 it is said to be basic in nature. At pH 7, the solution is neutral.