Question

You make 1 Liter of an aqueous solution containing 9.20 ml of 57.8 mM acetic acid and 56.2 mg of sodium acetate (MW = 82.0 g/mole). a. How many moles of acetic acid did you add? b. How many moles of sodium acetate did you add? c. What is the appropriate formula for calculating the pH of the above solution? d. What is the pH of the above solution? Is it acidic or basic? Slightly or strongly so? (Use the same scale as on HW 1)

Answer 1

Answer:

a) 5,3176x10⁻⁴ moles

b) 6,85x10⁻⁴ moles

c) The appropriate formula to calculate is Henderson-Hasselbalch.

d) pH = 4,86. Acidic solution but slighty

Explanation:

a) moles of acetic acid:

9,20x10⁻³L × 57,8x10⁻³M = 5,3176x10⁻⁴ moles

b) moles of sodium acetate:

56,2x10⁻³g ÷ 82,0 g/mole = 6,85x10⁻⁴ moles

c) The appropriate formula to calculate is Henderson-Hasselbalch:

pH= pka + log₁₀ $\frac{[A^-]}{[HA]}$

d) pH= 4,75 + log₁₀ $\frac{[6,85x10_{-4}]}{[5,3176x10_{-4}]}$

pH = 4,86

3 < pH < 7→ Acidic solution but slighty

I hope it helps!