Answer:
pH = 8.0
Explanation:
First, we have to calculate the moles of NaOH.
[tex]35.8 \times 10^{-3}L.\frac{0.020mol}{L} =7.2\times 10^{-4}mol[/tex]
Let's consider the balanced equation.
C₂H₄O₃ + NaOH ⇒ C₂H₃O₃Na + H₂O
The molar ratio C₂H₄O₃: NaOH: C₂H₃O₃Na is 1: 1: 1. So, when 7.2 × 10⁻⁴ moles of NaOH react completely with 7.2 × 10⁻⁴ moles of C₂H₄O₃ they form 7.2 × 10⁻⁴ moles of C₂H₃O₃Na.
The concentration of C₂H₃O₃Na is:
[tex]\frac{7.2\times 10^{-4}mol}{60.8 \times 10^{-3}L} =0.012M[/tex]
C₂H₃O₃Na dissociates according to the following equation:
C₂H₃O₃Na(aq) ⇒ C₂H₃O₃⁻(aq) + Na⁺(aq)
C₂H₃O₃⁻ comes from a weak acid so it undergoes basic hydrolisis.
C₂H₃O₃⁻ + H₂O ⇄ C₂H₄O₃ + OH⁻
If we know that pKa for C₂H₄O₃ is 3.9, we can calculate pKb for C₂H₃O₃⁻ using the following expression:
pKa + pKb = 14
pKb = 14 -3.9 = 10.1
10.1 = -log Kb
Kb = 7.9 × 10⁻¹¹
We can calculate [OH⁻] using the following expression:
[OH⁻] = √(Kb.Cb) where Cb is the initial concentration of the base
[OH⁻] = √(7.9 × 10⁻¹¹ × 0.012M) = 9.7 × 10⁻⁷ M
Now, we can calculate pOH and pH.
pOH = -log [OH⁻] = -log (9.7 × 10⁻⁷) = 6.0
pH + pOH = 14
pH = 14 - pOH = 14 - 6.0 = 8.0
Glycolic acid, which is a monoprotic acid and a constituent of sugar cane, the pH of the resulting solution at the equivalence point is 2 - 4.4.
The pH of a glycolic acid solution in a medical peel can be as low as 0.6, strong enough to damage the epidermis, while homemade peels have a higher pH, close to 2.5.
With this information, we can conclude that for glycolic acid, which is a monoprotic acid and a constituent of sugarcane, the pH of the resulting solution at the equivalence point is 2 - 4.4.
Learn more about glycolic acid in brainly.com/question/18506311
