Question

Dik: V HCN=100ml
M HCN=0,1M
V NaCN=50ml
M NaCN=0,2M
Ka HCN= 4×10^-5
dit: ph=..??

Answer 1

Jumlah mol HCN = 100 ml x 0,1 = 10 mmol
jumlah mol NaCN = 50 ml x 0,2 = 10 mmol

konsentrasi H+ = ka. a/g
                       = 4 x 10^-5 . 10/10
                       = 4 x 10^-5

ph = - log kosentrasi H+
     = - log 4 x 10^-5
     = 5 - log 4
     = 5 - 0.60
     = 4,40

jadi ph = 4,40