Question

La electroliza a 800 gr sol CuSO4, 20% se trece un curent de 7,72A
Se cere
Timpul de electroliza
Volumul de gaz degajat
Reacțiile care au loc la electroliza

Answer 1

ms = 800g sol. CuSO₄
C = 20%
I = 7,72A
F = 95000 C
Z = 2
A = 64

C = md/ms×100 ⇒ md = C×ms/100  = 20×800/100 = 160g CuSO₄

m = (A/Z×F)×I×T ⇔ m×Z×F = A×I×T ⇒ T = m×Z×F/A×I = (160×2×95000)/(64×7,72) = 6152,849s = 102,547 min = 1,7 h

Ionii prezenti in solutie: CuSO₄ ; Cu²⁺ ; SO₄⁻² 
H₂O ; H⁺ ; OH⁻

K(-) Cu⁺² ; H⁺
Cu⁺² +2e⁻ ⇒ Cu⁰↓
A(+) SO₄⁻²; OH⁻
OH⁻ -1e⁻ ⇒ OH·
·OH + ·OH ⇒ H₂O + 1/₂ O₂ ↑

In solutie: 2H⁺ + SO₄²⁻ ⇒ H₂SO₄

Reactia globala (totala) :

CuSO₄ + H₂O ⇒(electroliza) ⇒ Cu↓ + H₂SO₄ + 1/₂O₂↑

M CuSO₄ = 160g/mol

 n = md/M = 160/160 = 1 mol CuSO₄

1 mol CuSO₄...........................0,5×22,4L O₂
1 mol CuSO₄...........................x = 11,2 L O₂