What is the pH of a 0.1 M solution of sodium acetate (Ka for acetic acid = 1.8 x
Practice Questions
Q1
What is the pH of a 0.1 M solution of sodium acetate (Ka for acetic acid = 1.8 x 10^-5)?
4.75
5.25
9.25
10.25
Questions & Step-by-Step Solutions
What is the pH of a 0.1 M solution of sodium acetate (Ka for acetic acid = 1.8 x 10^-5)?
Step 1: Identify the given information. We have a 0.1 M solution of sodium acetate and the Ka (acid dissociation constant) for acetic acid, which is 1.8 x 10^-5.
Step 2: Calculate the pKa from the given Ka. Use the formula pKa = -log(Ka). So, pKa = -log(1.8 x 10^-5). This gives us pKa ≈ 4.74.
Step 3: Use the formula for the pH of a salt of a weak acid: pH = 14 + 0.5(pKa + logC), where C is the concentration of the salt (0.1 M in this case).
Step 4: Substitute the values into the formula. pH = 14 + 0.5(4.74 + log(0.1)).
Step 5: Calculate log(0.1). log(0.1) = -1.
Step 6: Substitute log(0.1) back into the equation: pH = 14 + 0.5(4.74 - 1).
Step 7: Simplify the equation: pH = 14 + 0.5(3.74).
Step 8: Calculate 0.5(3.74) = 1.87.
Step 9: Finally, add 14 + 1.87 to get the pH: pH = 15.87.
