Question

f a buffer solution is 0.520M in a weak acid (Ka=4.3×10 ^−6 ) and 0.150M in its conjugate base, what is the pH?

Answer 1

4.78

Step-by-step explanation:

To find the pH of a buffer solution, we can use the Henderson-Hasselbalch equation:

pH = pKa + log([A^-]/[HA])

where pKa is the negative logarithm of the acid dissociation constant, [A^-] is the concentration of the conjugate base, and [HA] is the concentration of the weak acid.

In this case, the weak acid is the protonated form of the conjugate base, so we can write:

HA + H2O ⇌ A^- + H3O+

The acid dissociation constant (Ka) for this reaction is given as 4.3×10^-6.

The concentration of the conjugate base is [A^-] = 0.150 M, and the concentration of the weak acid is [HA] = 0.520 M.

The pKa can be calculated from the Ka:

pKa = -log(Ka) = -log(4.3×10^-6) = 5.37

So, plugging the given values into the Henderson-Hasselbalch equation, we get:

pH = 5.37 + log(0.150/0.520) = 4.78

Therefore, the pH of the buffer solution is approximately 4.78.

Answer 2

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