Question

Sebanyak 50ml larutan NaOH 0,1M dicampurkan dgn 50ml larutan CH3COOH 0,1M. Tentukan pH campuran tsb... (Ka=10^-5)

Answer 1

NaOH+ CH3COOH ---> CH3COONa + H2O
M 5 mmol 5 mmol - -
B 5 mmol 5 mmol 5 mmol 5 mmol
S - - 5 mmol 5 mmol

[OH¯] = akar kw/ka . M garam
= akar 1 x 10¯¹⁴/ 1x10¯5 . mmol garam /v. tot
= akar 1 x 10¯9 5/100
= akar 5 x 10¯¹¹
= 5½ x 10¯55
poh = - log ( 5 ½ c 10¯5,5)
= 5,5 - ½ log 5
= 5,5 - 0,35
= 5,15
ph = pkw - poh
= 14 - 5,15
= 8,85