In: Chemistry
Calculate the pH after 10 mL of 1.0 M sodium hydroxide is added to 60 mL of 0.5 M acetic acid.
Total volume = 10ml +60 ml = 70 ml
New concentration of CH3COOH = 60*0.5/70= 0.43 M
New concentration of NaOH = 10*1.0/70= 0.14 M
Ice table:
CH3COOH + OH- ----- > CH3COO- H2O
I 0.43 0.14 0
C -0.14 -0.14 0.14
E 0.29 0 0.14
We know that pKa = 4.74
And according to the handerson equation;
pH = pka + log [CH3COO-] / [CH3COOH]
= 4.74 + log 0.14 /0.29
= 4.74 + log 0.483
= 4.74 +(-0.316)
= 4.42