A solution of weak base has pH = 7.95. What are the concentrations of the weak base and its conjugate acid ion in this solution? Ka = 6.28*10(-5). BOH <-------> B(+) + OH(-)
1 Answer
Start by calculating the concentration of the hydroxide ions by using the given value for pH.
Now use the equilibrium equation to solve for the initial concentration of the base, which I'll call Z; this in turn will get you the concentration of the base at equilibrium. Set up an ICE chart for your reaction
...
I......Z..............0.............0
C...(-x)............(+x)........(+x)
E...Z-x..............x............x
Don't forget to use the base dissociation constant,
The expression for
Since you know that the value of
It's same to assume that Z will be
This means that the concentration of the weak base and of its conjugate acid in solution will be
SIDE NOTE. I'm assuming these concentrations to be in mol/L.