Calculate the ratio [NH 3 ]/[NH 4 + ] in ammonia/ammonium chloride buffered solutions with the following pH values: a. pH = 9.00 b. pH = 8.80 c. pH = 10.00 d. pH = 9.60

Interpretation:

Different pH values of a solution containing NH3 and NH4+ are given. The ratio, [NH3]/[NH4+] is to be calculated.

Concept introduction:

The pOH value is the measure of OH− ions. The relation between pOH and pKb is given by Henderson-Hassel Bach equation. According to this equation,

pOH=pKb+log[Conjugate acid][Weak base]

Explanation

To determine the pOH value of the solution

The relation between pH and pOH is,

pH+pOH=14

Where,

• pH is a measure of concentration of H+ .
• pOH is a measure of concentration of OH− .

Substitute the value of pOH in above equation.

pH+pOH=149.00+pOH=14pOH=5.00_

To determine the ratio [NH3]/[NH4+]

The value of Kb for NH3 is 1.8×10−5 .

The pOH value of solution is 5.00 .

The pOH is calculated using the Henderson-Hassel Bach equation,

pOH=pKb+log[Conjugate acid][Weak base]

Where,

• pOH is the measure of OH− ions.
• pKb is the measure of basic strength.

The formula of pKb is,

pKb=−logKb

Where,

• Kb is base equilibrium constant.

Substitute the value of pKb in the Henderson-Hassel Bach equation.

pOH=−logKb+log[Conjugate acid][Weak base]

Substitute all the given values in the above equation

Interpretation:

Different pH values of a solution containing NH3 and NH4+ are given. The ratio, [NH3]/[NH4+] is to be calculated.

Concept introduction:

The pOH value is the measure of OH− ions. The relation between pOH and pKb is given by Henderson-Hassel Bach equation. According to this equation,

pOH=pKb+log[Conjugate acid][Weak base]

Interpretation:

Different pH values of a solution containing NH3 and NH4+ are given. The ratio, [NH3]/[NH4+] is to be calculated.

Concept introduction:

The pOH value is the measure of OH− ions. The relation between pOH and pKb is given by Henderson-Hassel Bach equation. According to this equation,

pOH=pKb+log[Conjugate acid][Weak base]

Interpretation:

Different pH values of a solution containing NH3 and NH4+ are given. The ratio, [NH3]/[NH4+] is to be calculated.

Concept introduction:

The pOH value is the measure of OH− ions. The relation between pOH and pKb is given by Henderson-Hassel Bach equation. According to this equation,

pOH=pKb+log[Conjugate acid][Weak base]