Jawaban:

Basa kuat

[OH] = b x M

b = valensi basa = jumlah OH

pH = 14 - pOH

pOH = - log OH^-

RUMUS MOLARITAS

M = mol/liter = g/Mr x 1000/V

===================================

a. M NaOH = g/Mr x 1000/v

= 8/40 × 1000/250

= 0,8

OH = 1 x 0,8

= 8 x 10^-1

pOH = - log 8 x 10^-1

= 1 - log 8

pH = 14 - (1-log8)

= 13 + log 8

___________________________

b. (2,4 mmol=0,0024 mol)

M KOH = mol/liter

= 0,0024/3

= 0,0008

OH = 1 x 0,0008

= 8 x 10^-4

pOH = - log 8 x 10^-4

= 4 - log 8

pH = 14 - (4-log8)

= 11 + log 8

______________________

c. M Ba(OH)2 = 1 x 10^-3

OH = 2 x 1 × 10^-3

= 2 x 10^-3

pOH = - log 2 x 10^-3

= 3 - log 2

pH = 14 - (3-log2)

= 11 + log 2

______________________

d. M NaOH = 1 x 10^-9

OH = 1 x 1 x 10^-9

= 1x 10^-9

pOH = - log 1 x 10^-9

= 9

pH = 14 - 9

= 5