jwb

reaksi  HCOOH sm KOH = HCOOH + KOH → HCOOK + H2O

perbandingan reaksi = 1:1 (HCOOH, KOH)

20 ml larutan HCOOHbereaksi dgn 20 ml dri 40 ml larutanKOH

HCOO- + H2O ⇌ HCOOH + OH- (ionisasi)

Kc = [HCOOH] [OH-] : [HCOO-]

Kc = [H+] [OH-] : [HCOO-] (terdeprotonasi)

[HCOO-] = mol HCOOH yg bereaksi : volume campuran

= 0,3 M x 0,02 L / 0,06 L

= 0,1 M

Kw = [H+] [OH-] (konsentrasi H+)

1 x 10^-14 = [H+] (0,1 M x 10^-3)

[H+] = 1 x 10^-12 M

pH = -log[H+]

= -log(1 x 10^-12)

= 12

pH campuran dri 20 ml larutan HCOOH 0,3 M dan 40 ml larutan KOH 0,1 M = 12