What is the pH created by?

Question

combining 3.00 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HCl(aq)?

with 8.00 mL of the 0.10 M HC2H3O2(aq)?

What are the pH values if you take into account that the 8.00 mL of 0.10 M Acid was first diluted with 100 mL of water?

Answer 1

Moles NaOH = 0.0030 L x 0.10 M = 0.00030

moles HCl = 0.008 L x 0.10 M = 0.00080

Moles H+ in excess = 0.00050

total volume = 0.011 L

[H+] = 0.00050/ 0.011 =0.0455 M

pH = 1.34

moles NaOH = 0.00030

moles acetic acid = 0.00080

CH3COOH + OH- >> CH3COO- + H2O

moles acid = 0.00080 - 0.00030 = 0.00050

Moles acetate = 0.00030

concentration acetic acid = 0.00050/ 0.011 =0.0455 M

concentration acetate = 0.00030 / 0.011 =0.0273 M

pKa = 4.74

pH = 4.74 + log 0.0273/ 0.0455 =4.52