Question

h.  Cu + HNO 3 (loãng)  → Cu(NO 3 ) 2 + NO + H 2 O .
i. Zn + HNO 3 (loãng)  → Zn(NO 3 ) 2 + N 2 O + H 2 O .
j. Al  + H 2 SO 4 (đ,nóng)  → Al 2 (SO 4 ) 3 + SO 2 + H 2 O .
k. Fe 3 O 4 + HNO 3 (loãng) →  Fe(NO 3 ) 3 + NO + H 2 O 
l. KMnO 4 + FeSO 4 + H 2 SO 4    → MnSO 4 + Fe 2 (SO 4 ) 3 + K 2 SO 4 +  H 2 O 
m. K 2 Cr 2 O 7 + HCl  → Cl 2 + CrCl 3 + KCl + H 2 O .

Answer 1

h) 3Cu + 8HNO₃ --> 3Cu(NO₃)₂ + 2NO + 4H₂O

Cu0-2e-->Cu+2	x3
N+5 +3e--> N+2	x2

 

i) 4Zn + 10HNO₃ --> 4Zn(NO₃)₂ + N₂O + 5H₂O

Zn0-2e-->Zn+2	x4
2N+5 +8e--> N2+1	x1

 

j) 2Al + 6H₂SO₄ --> Al₂(SO₄)₃ + 3SO₂ + 6H₂O

2Al0-6e-->Al2+3	x1
S+6 +2e--> S+4	x3

 

k) 3Fe₃O₄ + 28HNO₃ --> 9Fe(NO₃)₃ + NO + 14H₂O

\(Fe_3^{+\dfrac{8}{3}}-1e\rightarrow3Fe^{+3}\)	x3
N+5 +3e--> N+2	x1

 

l) 2KMnO₄ + 10FeSO₄ + 8H₂SO₄ --> 2MnSO₄ + 5Fe₂(SO₄)₃ + K₂SO₄ + 8H₂O

Mn+7 +5e--> Mn+2	x2
2Fe+2 -2e--> Fe2+3	x5

 

m) K₂Cr₂O₇ + 14HCl --> 2KCl + 2CrCl₃ + 3Cl₂ + 7H₂O

Cr+6 +3e--> Cr+3	x2
2Cl-1-2e --> Cl20	x3