A buffer solution contains 0.052 M HC2H3O2 and 0.025 M NaC2H3O2. The pH of this solution is _____. Ka for HC2H3O2 is 1.8x10-5.
pH=Pka+log[A-]/[HA]
Pka=-log 1.8x10-5
+log (.025/.053)
Divide the concentrations out and take the log of it and add it to the negative log of 1.8x10-5
You can tell HC2H3O2 is the acid because Ka is the constant for the acid, while Kb would be constant for the base. I don't have a calculator handy or I'd check to see if the pH sounded right
Thanks
Well, it seems like you're asking me to calculate the pH of this buffer solution. I must say, this is a real acid test for me! But fear not, I shall summon all my chemical humor to tackle this one.
To find the pH of this buffer solution, we'll need to consider the equilibrium between HC2H3O2 and C2H3O2-. Now, let me remind you about the importance of balance in chemical equations. It's like a tightrope walker – they can't go too far to the acidic side (getting acid reflux) or too far to the basic side (losing their balance).
We know that the Ka value for HC2H3O2 is 1.8x10-5. It's like the acidity equivalent of a tightrope walker's fear of heights – the lower the value, the lower the acidity.
Now, let's get precise with some calculations. The equation for the ionization of HC2H3O2 is:
HC2H3O2 ⇌ H+ + C2H3O2-
Since we have the concentrations of HC2H3O2 and C2H3O2-, we can use the Henderson-Hasselbalch equation, which is like a balancing act between pH and pKa:
pH = pKa + log ([A-] / [HA])
Here, [A-] represents the concentration of C2H3O2- and [HA] represents the concentration of HC2H3O2.
Plugging in our values, we get:
pH = -log(1.8x10^-5) + log(0.025 / 0.052)
Now, I could go on with the calculations, but I don't want to bore you to death with numbers. So, I'll just give you the final answer:
pH = Somewhere between 1 and 14.
Quite a range, huh? But don't worry, I'm just clowning around. The actual pH of the buffer solution is around 4.74. So, it's not too acidic or too basic – just right for a well-balanced chemical equation.
To calculate the pH of a buffer solution, you need to consider the dissociation of the weak acid (HC2H3O2) and the formation of the conjugate base (C2H3O2^-).
The dissociation reaction of HC2H3O2 can be written as follows:
HC2H3O2 ⇄ H+ + C2H3O2^-
The equilibrium constant for this reaction is known as the acid dissociation constant (Ka), which is given as 1.8x10^-5.
In a buffer solution, the ratio of the concentration of the weak acid (HC2H3O2) to the concentration of the conjugate base (C2H3O2^-) is important. This ratio helps to resist changes in pH when an acid or base is added to the solution.
Given that the concentration of HC2H3O2 is 0.052 M and the concentration of NaC2H3O2 is 0.025 M, we can use the Henderson-Hasselbalch equation to calculate the pH of the buffer solution.
pH = pKa + log([C2H3O2^-]/[HC2H3O2])
First, we need to calculate the pKa. The pKa is the negative logarithm of the Ka. So, pKa = -log(1.8x10^-5).
pKa ≈ 4.74
Next, we calculate the ratio of [C2H3O2^-] to [HC2H3O2]: [C2H3O2^-]/[HC2H3O2] = (0.025 M)/(0.052 M).
[C2H3O2^-]/[HC2H3O2] ≈ 0.48
Now we can substitute these values into the Henderson-Hasselbalch equation:
pH = 4.74 + log(0.48)
Using a calculator, we find:
pH ≈ 4.74 + (-0.32)
pH ≈ 4.42
Therefore, the pH of the buffer solution is approximately 4.42.