suatu larutan NaOH 1 liter memiliki pH=12 tentuka massa NaOHyang terlarut dalam larutan NaOH tersebut (Mr Na=23, Mr O=16, Mr H=1)

NaOH
V = 1 L = 1000 mL
pH = 12

ditanya = massa NaOH ... ?

*Mr NaOH
Mr = Ar Na + Ar O + Ar H
Mr = 23 + 16 + 1
Mr = 40 gram/mol

*pH + pOH = 14
pOH = 14 - pH
pOH = 14 - 12
pOH = 2

*pOH = - log [OH^-]
....... 2 = - log [OH^-]
. 10^-2 = [OH^-]
[OH^-] = 10^-2

*[OH^-] = b . Mb
.. 10^-2 = 1 . Mb
...... Mb = 10^-2

*Massa NaOH
............. M = m/Mr . 1000/mL
....... 10^-2 = m/40 . 1000/1000
....... 10^-2 = m/40
10^-2 . 40 = m
........... 0,4 = m
............. m = 0,4 gram