Larutan ca(oh)2 mempunyai PH 12 + log 4. Massa ca(oh)2 dalam 200 mL larutan tersebut sebanyak...... mg. (Mr ca(oh)2 = 74 )

pH = 12 + log 4
pOH = 2 - log 4
OH- = 4.10^-2 M
OH- = b Mb
4.10^-2 = 2Mb
Mb = 2.10^-2 M
M = m/Mr x 1000/ml
0,02 = m/74 x 1000/200
m = 0,296 gram
= 296 mg