1.
stim ca pH = -lg[H3O+]
si pOH = -lg[HO-]
intre pH si pOH avem relatia
pH + pOH = 14
a. pH = -lg[10-12] = 12
=> pOH = 14-12 = 2
b. pOH = -lg[10-5] = 5
=> pH = 14-5 = 9
c. pH = -lg[10-2] = 2
=> pOH = 14-2 = 12
d. pH = -lg[10-72] = 7
pOH = 14-7 = 7
e. pOH = -lg[10-4] = 4
=> pH = 14-4 = 10
f. pOH = -lg[10-11] = 11
=> pH = 14-11 = 3
2.
[H3O+] = 10la-pH
[HO-] = 10la-pOH
a. [H3O+] = 10la-7 mol/L
pOH = 14-7 = 7
=> [HO-] = 10la-7 mol/L
b. [HO-] = 10la-3 mol/L
pH = 14-3 = 11
=> [H3O+] = 10la-11 mol/L
c. [H3O+] = 10la-6 mol/L
pOH = 14-6 = 8
=> [HO-] = 10la-8 mol/L
d. [HO-] = 10la-12 mol/L
pH = 14-12 = 2
=> [H3O+] = 10la-2 mol/L
3.
a)
stim Cm = roxc%x10/miu, miuHCl = 36,5 g/mol
=> Cm = 1,15x0,3x10/36,5 = 0,1 mol/L (rotunjit)
HCl = acid tare => [H3O+] = Cm => pH = -lgCm
= -lg10-1 = 1
=> pOH = 14- 1 = 13
b)
stim Cm = roxc%x10/miu, miuNaOH = 40 g/mol
=> Cm = 1,02x0,0392x10/40 = 0,01 mol/L (rotunjit)
NaOH = baza tare => [HO-] = Cm => pOH = -lgCm
= -lg10-2 = 2
=> pH = 14-2 = 12
