suatu larutan NaOH (Mr = 40g/mol) memiliki 20% tentukan kemolalan larutan NaOH tersebut

diketahui : Mr = 40
dalam 100 gr larutan NaOH terdapat 20% NaOH
NaOH = [tex] \frac{20}{100} x 100[/tex] = 20 gr
air = 100 - 20 = 80
ditanya: kemolalan larutan NaOH = ......?
jawab:
m = [tex] \frac{gr}{Mr} x \frac{1000}{P} [/tex]
= [tex] \frac{20}{40} x \frac{1000}{80} [/tex]
= [tex] \frac{1}{2} x \frac{100}{8} [/tex]
= 6.25 molal