Question

A solution is prepared at that is initially in ammonia , a weak base with , and in ammonium bromide . Calculate the pH of the solution. Round your answer to decimal places.

Answer 1

The question is incomplete, here is the complete question:

A solution is prepared at 25°C that is initially 0.22 M in ammonia
`(NH_3)`, a weak base with
`K_b=1.8* 10^(-5)`, and 0.073 M in ammonium chloride
`(NH_4Cl`. Calculate the pH of the solution. Round your answer to 2 decimal places.

Answer: The pH of the solution is 9.74

Step-by-step explanation:

The chemical equation for the reaction of ammonia with hydrochloric acid follows:

`NH_3+HCl\rightarrow NH_4Cl`

To calculate the pOH of basic buffer, we use the equation given by Henderson Hasselbalch:

`pOH=pK_b+\log(([salt])/([base]))`

`pOH=pK_b+\log(([NH_4Cl])/([NH_3]))`

We are given:

`pK_b` = negative logarithm of base dissociation constant of ammonia = 4.74

`[NH_4Cl]=0.073M`

`[NH_3]=0.22M`

pOH = ?

Putting values in above equation, we get:

`pOH=4.74+\log((0.073)/(0.22))\\\\pOH=4.26`

To calculate pH of the solution, we use the equation:

`pH+pOH=14\\\\pH=14-4.26=9.74`

Hence, the pH of the solution is 9.74