Question

If a buffer solution is 0.250 M 0.250 M in a weak base ( K b = 8.0 × 10 − 5 ) Kb=8.0×10−5) and 0.540 M 0.540 M in its conjugate acid, what is the pH ?

Answer 1

9.57

Step-by-step explanation:

Given that:

`pK_(b)=-\log\ K_(b)=-\log(8.0* 10^(-5))=4.1`

Considering the Henderson- Hasselbalch equation for the calculation of the pOH of the basic buffer solution as:

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

So,

`pOH=4.1+\log(0.540)/(0.250)=4.43`

pH + pOH = 14

So, pH = 14 - 4.43 = 9.57