Question

500 mL larutan H2SO4 mempunyai PH = 2 jika Mr H2SO4 = 98, Maka banyaknya H2SO4 yang di larutkan adalah ... g?

Answer 1

PH = -log[H+]
2 = -log [H+]
-2 = log [H+]
[H+] = 10^-2 = 0,1 Mol/L

mol [H+] = 2 x mol H2SO4
0,1 mol = 2 x mol H2SO4
mol H2SO4 = 0,1 mol/2 = 0,05 mol -> 0,05 M

M = gr/Mr x 1000/v(ml)
0,05 M = gr/98 x 1000/500 ml
gr = (0,05 M x 98 x 500 ml)/1000
= 2450/1000 = 2,45 gram

jadi banyaknya H2SO4 yg dilarutkan adalah 2,45 gram.

Answer 2

Diket
pH H2SO4  = 2
Mr = 98
Jawab
pH = -log[H+]
2   = -log [H+]
-2  = log [H+]
[H+] = 10^-2 = 0,1 Mol/L

mol [H+]    = 2 x mol H2SO4
0,1 mol      = 2 x mol H2SO4
mol H2SO4 = 0,1 mol/2
                 = 0,05 mol -> 0,05 M

M        = gr/Mr x 1000/v(ml)
0,05 M = gr/98 x 1000/500 ml
gr        = (0,05 M x 98 x 500 ml)/1000
          = 2450/1000  
          = 2,45 gram