Question

Hitung pH dari
A) 2,4 gr CH3COOH dlm 100 ml larutan. Ka CH3COOH = 1 * 10^-5
B) 0,37 gr Ca(OH)2 dalam 50 ml larutan

Answer 1

A) CH3COOH = asam lemah
  [H+] = √Ka x M
M = mol/V(L)
mol = gr/Mr = 2,4 /60 = 0,04
M = 0,04/0,1 = 0,4
 [H+] = √10^5 x 0,4  = 4 x 10^6
pH = 6 - log 4

b) Ca(OH)2 = BASA KUAT
   [OH-] = M  x Jumlah ion OH -
M = mol/V(L)
mol = gr/Mr = 0,37 gr /74 = 0,005

M = 0,005/ 0,05 = 0,1
[H+] = 0,1 x 2 = 2 x 10^1
poH = 1- log 2
pH = 14 -(1- log 2)
     = 13 + log 2