Calculate the pH of a buffer solution containing 0.1 M acetic acid and 0.1 M sod

₹0.0

Question: Calculate the pH of a buffer solution containing 0.1 M acetic acid and 0.1 M sodium acetate.

Options:

Correct Answer: 5.76

Solution:

Using Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]); pKa of acetic acid = 4.76, so pH = 4.76 + log(1) = 4.76

Calculate the pH of a buffer solution containing 0.1 M acetic acid and 0.1 M sodium acetate.

Calculate the pH of a buffer solution containing 0.1 M acetic acid and 0.1 M sodium acetate.

Step 1: Identify the components of the buffer solution. We have acetic acid (HA) and sodium acetate (A-).
Step 2: Determine the concentrations of the components. Both acetic acid and sodium acetate are at 0.1 M.
Step 3: Recall the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]).
Step 4: Find the pKa value for acetic acid, which is 4.76.
Step 5: Calculate the ratio of the concentrations: [A-] (sodium acetate) is 0.1 M and [HA] (acetic acid) is 0.1 M. So, [A-]/[HA] = 0.1/0.1 = 1.
Step 6: Calculate the logarithm of the ratio: log(1) = 0.
Step 7: Substitute the values into the Henderson-Hasselbalch equation: pH = 4.76 + 0.
Step 8: Simplify the equation to find the pH: pH = 4.76.

Buffer Solutions – A buffer solution resists changes in pH upon the addition of small amounts of acid or base, typically composed of a weak acid and its conjugate base.
Henderson-Hasselbalch Equation – A formula used to calculate the pH of a buffer solution, expressed as pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the conjugate base and [HA] is the concentration of the weak acid.
pKa Value – The negative logarithm of the acid dissociation constant (Ka) of a weak acid, indicating the strength of the acid.