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 ?

9.57

Explanation:

Given that:

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

So,  

pH + pOH = 14  

So, pH = 14 - 4.43 = 9.57

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).