What is the pH of the solution created by combining 2.80 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HC2H3O2(aq)?
I got 1.3. is that correct?
STEP 1: STOICHIOMETRY to find moles C2H3O2- formed and HC2H3O2 remaining. All NaOH was used up, so that's how many moles reacted with the HC2H3O2 and also how many moles C2H3O2- formed.
STEP 2: EQUILIBRIUM of HC2H3O2 with H+ and C2H3O2-. Change the moles of HC2H3O2 and C2H3O2- into molarities by dividing by the TOTAL VOLUME (0.00280 L + .008L = .01080 L) and plug those into the equilibrium equation. (The value of K for HC2H3O2, or acetic acid, is 1.8 X 10 ^-5)
STEP 3: SOLVE FOR pH
SUMMARY: NaOH is a strong base - Stoichiometry
Acetic acid is a weak acid - Equilibrium
Use the equilibrium equation to solve for [H+], then the pH
No, 1.3 is not the answer. Follows Bill's instructions OR use the Henderson-Hasselbalch equation.
To find the pH of the solution, you need to calculate the concentration of the hydronium ion (H3O+) in the solution. The concentration of the hydronium ion can be calculated by using the equilibrium constant expression for the dissociation of the weak acid HC2H3O2.
The balanced chemical equation for the dissociation of HC2H3O2 is:
HC2H3O2(aq) + H2O(l) ⇌ C2H3O2^-(aq) + H3O+(aq)
The equilibrium constant expression for this reaction is:
Ka = [C2H3O2^-][H3O+] / [HC2H3O2]
The Ka value for HC2H3O2 is given in the question. Since it is not provided, it is important to note that Ka = 1.8 x 10^-5 for HC2H3O2.
To solve for [H3O+], we'll use the Ka expression and the initial concentrations of HC2H3O2 and NaOH. Here's the step-by-step calculation:
Step 1: Calculate the moles of HC2H3O2 and NaOH.
moles of HC2H3O2 = concentration of HC2H3O2 × volume of HC2H3O2
moles of NaOH = concentration of NaOH × volume of NaOH
Step 2: Calculate the concentrations of HC2H3O2 and NaOH.
concentration of HC2H3O2 = moles of HC2H3O2 / total volume of solution
concentration of NaOH = moles of NaOH / total volume of solution
Step 3: Use the balanced chemical equation to determine the ratio between HC2H3O2 and H3O+ ions.
From the equation, the ratio is 1:1. So the concentration of H3O+ ions will be the same as the concentration of HC2H3O2.
Step 4: Calculate the equilibrium concentration of H3O+ ions using the quadratic formula.
[H3O+] = (Ka × concentration of HC2H3O2)^0.5
Step 5: Calculate the pH of the solution by taking the negative logarithm of [H3O+].
pH = -log10[H3O+]
By following these steps and plugging in the values, you should be able to find the correct pH of the solution.