lp 7

Question 1

Caracterul oxidant al H₂O₂ (3%)
Preparare PbS

Answer 1

Na₂S(aq) + Pb(NO₃)₂(aq) → PbS(s)↓ + 2NaNO₃(aq)

Question 2

Caracterul oxidant al H₂O₂ (3%) - mediu neutru:
PbS + H₂O₂ → oxidarea sulfurii la sulfat

Answer 2

PbS(s) + 4H₂O₂(aq) → PbSO₄(s) + 4H₂O(l)

Question 3

Caracterul oxidant al H₂O₂ (3%) - mediu acid:
H₂O₂ + H₂SO₄ + KBr → oxidarea bromurii la brom

Answer 3

H₂O₂ + H₂SO₄ + 2KBr → Br₂ + K₂SO₄ + 2H₂O

Question 4

Caracterul oxidant al H₂O₂ (3%) - mediu bazic:
MnSO₄ + NaOH + H₂O₂ → oxidarea Mn²⁺

Answer 4

MnSO₄ + 2NaOH + H₂O₂ → MnO₂(s)↓ + Na₂SO₄ + 2H₂O

Question 5

Caracterul oxidant al H₂O₂ (3%):
FeSO₄ + NaOH + H₂O₂ → oxidarea Fe²⁺

Answer 5

2FeSO₄ + 4NaOH + H₂O₂ → 2Fe(OH)₃(s)↓ + 2Na₂SO₄ + 2H₂O

Question 6

Caracterul oxidant al H₂O₂ (3%):
CoSO₄ + NaOH + H₂O₂ → oxidarea Co²⁺

Answer 6

CoSO₄ + NaOH + H₂O₂ + H₂O → Co₂O₃ + H₂O + Na₂SO₄

Question 7

Caracterul reducator al H₂O₂ (3%) - mediu acid:
KMnO₄ + H₂SO₄ + H₂O₂ → reducerea Mn⁷⁺

Answer 7

2KMnO₄ + 3H₂SO₄ + 5H₂O₂ → 2MnSO₄ + K₂SO₄ + 5O₂(g)↑ + 8H₂O

Question 8

Caracterul reducator al H₂O₂ (3%) - mediu acid:
K₂CrO₄ + H₂SO₄ + H₂O₂ → reducerea Cr⁶⁺
(CrO₄²⁻ devine Cr₂O₇²⁻ în acid)

Answer 8

K₂Cr₂O₇ + 4H₂SO₄ + 3H₂O₂ → Cr₂(SO₄)₃ + K₂SO₄ + 3O₂(g)↑ + 7H₂O

Question 9

Caracterul reducator al H₂O₂ (3%) - mediu bazic:
K₃[Fe(CN)₆] + KOH + H₂O₂ → reducerea Fe³⁺

Answer 9

2K₃[Fe(CN)₆] + 2KOH + H₂O₂ → 2K₄[Fe(CN)₆] + O₂(g)↑ + 2H₂O

Question 10

Caracterul reducator al H₂O₂ (3%) - mediu bazic:
AgNO₃ + KOH + H₂O₂ → reducerea Ag⁺

Answer 10

2AgNO₃ + 2KOH + H₂O₂ → 2Ag(s)↓ + 2KNO₃ + O₂(g)↑ + 2H₂O

Question 11

Formarea si caracterul oxidant al compusilor peroxidici ai cromului(VI):

Answer 11

K₂Cr₂O₇ + H₂SO₄ + 4H₂O₂ -(eter etilic)→ 2CrO₅ + K₂SO₄ + 5H₂O

Question 12

Formarea si caracterul oxidant al compusilor peroxidici ai cromului(VI):
Caracter oxidant: CrO₅ + H₂SO₄ + KI → Oxidarea iodurii cu peroxid de Cr(VI)

Answer 12

2CrO₅ + 7H₂SO₄ + 10KI → Cr₂(SO₄)₃ + 5I₂ + 5K₂SO₄ + 7H₂O

Question 13

NaBrO + H₂O₂ → (H₂O₂ ca reducator)

Answer 13

NaBrO + H₂O₂ → NaBr + H₂O + O₂(g)↑

Question 14

KMnO₄ + H₂O₂ → (H₂O₂ ca reducator)

Answer 14

Echilibrată (Acid):
2KMnO₄ + 3H₂SO₄ + 5H₂O₂ → 2MnSO₄ + K₂SO₄ + 5O₂(g)↑ + 8H₂O
Echilibrată (Bazic/Neutru):
2KMnO₄ + 3H₂O₂ → 2MnO₂(s)↓ + 2KOH + 3O₂(g)↑ + 2H₂O

Question 15

H₂O₂ + FeSO₄ + NaOH

Answer 15

FeSO₄ + 2NaOH → Fe(OH)₂(s) + Na₂SO₄ 2Fe(OH)₂(s) + H₂O₂(aq) → 2Fe(OH)₃(s)↓