In: Chemistry
Consider the following 50.00 mL of 0.300 M acetic acid (HC2H3O2) was titrated with 0.200 M potassium hydroxide (KOH).
HC2H3O2 + KOH H2O + C2H3O2-K+
A. Calculate the pH of the solution when 20.00 mL of 0.200 M KOH is added.
B. Calculate the pH of the solution when 40.00 mL of 0.200 M KOH is added.
C. Calculate the pH of the solution when 50.00 mL of 0.200 M KOH is added.
A. Calculate the pH of the solution when 20.00 mL of 0.200 M KOH is added.
millimoles of CH3COOH = 50 x 0.3 = 15
millimoles of KOH = 20 x 0.2 = 4
CH3COOH + KOH -------------------------> CH3COOK + H2O
15 4 0 0
11 0 4 4
pH = pKa + log [CH3COOK / CH3COOH ]
pH = 4.74 + log (4 /11)
pH = 4.30
B. Calculate the pH of the solution when 40.00 mL of 0.200 M KOH is added.
millimoles of KOH = 40 x 0.2 = 8
CH3COOH + KOH -------------------------> CH3COOK + H2O
15 8 0 0
7 0 8 8
pH = pKa + log [CH3COOK / CH3COOH ]
pH = 4.74 + log (8 /7)
pH = 4.80
C. Calculate the pH of the solution when 50.00 mL of 0.200 M KOH is added.
millimoles of KOH = 50 x 0.2 = 10
CH3COOH + KOH -------------------------> CH3COOK + H2O
15 10 0 0
1 0 10 10
pH = pKa + log [CH3COOK / CH3COOH ]
pH = 4.74 + log (10 /1)
pH = 5.74