Question

REDOX WS1

Answer 1

A.
Cr⁺¹ + Sn⁺⁴ ⇒ Cr⁺³ + Sn⁺²
Cr⁺¹ ⇒ Cr⁺³ + 2e⁻
The half-reaction of oxidation: chrome is an electron donor, losses 2 electrons ie it is oxidized
2e⁻ + Sn⁺⁴ ⇒ Sn⁺²
The half-reaction of reduction: tin is an electron acceptor, receives 2 electrons, ie it is reduced

b.
3Hg⁺² + 2Fe ⇒ 3Hg + 2Fe⁺³
2Fe ⇒  2Fe⁺³ + 6e⁻ 
The half-reaction of oxidation: iron is an electron donor, losses 3 electrons ie it is oxidized
6e⁻ + 3Hg⁺² + ⇒ 3Hg 
The half-reaction of reduction: mercury is an electron acceptor, receives 2 electrons, ie it is reduced

c.
2As + 3Cl₂ ⇒ 2AsCl₃
2As ⇒ 2As⁺³ + 6e⁻ 
The half-reaction of oxidation: arsenic is an electron donor, losses 3 electrons ie it is oxidized
6e⁻ + 3Cl₂ ⇒ 6Cl⁻
The half-reaction of reduction: chlorine is an electron acceptor, receives 1 electron, ie it is reduced

d.
NaBr + Cl₂ ⇒ NaCl + Br₂ 
2Br⁻ ⇒  Br₂ + 2e⁻ 
The half-reaction of oxidation: bromine is an electron donor, losses 1 electron ie it is oxidized
2e⁻ + Cl₂ ⇒ 2Cl⁻
The half-reaction of reduction: chlorine is an electron acceptor, receives 1 electron, ie it is reduced

e.
Fe₂O₃ + 3CO ⇒ 2Fe + 3CO₂
3C⁺² ⇒ 3C⁺⁴ + 6e⁻
The half-reaction of oxidation: carbon is an electron donor, losses 2 electrons ie it is oxidized
6e⁻ +  2Fe⁺³ ⇒ 2Fe 
The half-reaction of reduction: iron is an electron acceptor, receives 3 electrons, ie it is reduced