Question

Jika 0,74 gram Ca(OH)2 [mr=74] dilarutkan dalam 2 liter air mmpunyai harga ph sbesar?

Answer 1

0.74 / 74 = 10^-2 mol Ca(OH)2
M = n / V = 10^-2 / 2 = 5 . 10^-3 M
[OH-] = M . valensi anion = 5 . 10^-3 . 2 = 10^-2
pOH = 2 , pH = 14-2 = 12

Answer 2

Ca(OH) = M Ca(OH)2 /mr Ca(OH)2
= 0,74 / 74 = 0,01

ca(oh)2 = n/v = 0,01 / 2 = 0,005
(oh) = 2 x 0,005 = 0,01
poh= -log (oh)
=-log 10-2
=2
ph = 14-2
=2