mohon jawabannya kakak

Mol NaOH = 0,5 x 20 = 10 mmol
Mol HCN = 0,5 x 20 = 10 mmol
NaOH + HCN -> NaCN + H2O
Krn koefisien NaCN sebanding dg NaOH dan HCN, mk jml NaCN = 10 mmol.
[OH-] = √(Kw/Ka) x Mgaram
= √(10^-14/10^-5) x (10/40)
= 5 x 10^-5,5
pOH = 5,5-log 5
pH = 8,5 + log 5