jawab pake caranya ya. Yang nomor 3 sama 4

3.)
[tex]NaOH => Na + OH \\ mol \: NaOH = gram \div mr \\ = > \frac{8}{40} = 0.2 \\ mol \: OH = 0.2 \: mol \: NaOH \times \frac{1 \: mol \: oh}{1 \: mol \: naoh} \\ = > 0.2 \: mol \: OH \\ jadi \: M \: = \: \frac{mol \: oh}{liter} = \frac{0.2}{1} = 0.2[/tex]
4.)
M = (gram / Mr) × (1000/ ml)
M = (8,5 / 17 )×( 1000/500)
M = (8,5/17)×2
M = 17/17 = 1

OH = √(M × Kb)
=> √(1×1,8 × 10^-5)
=>√(18×10^-6)
=>(√18) × 10^-3

pOH= -log (OH)
=> -log ((√18) × 10^-3)
=>3 - log 18

pH= 14 - pOH
=>14 - (3-log √18)
=>11+log √18

semoga membantu:) ;)