Write the equations for the reaction: Mg + H2SO4
(Concentrated)
Determine oxidants and reducing agents in the above equation. Determine the EMF value using the standard capacity reduction table.
Chemical equations?
2018-04-10 9:32 am
回答 (1)
2018-04-10 3:54 pm
Mg + 2H₂SO₄ → MgSO₄ + SO₂ + 2H₂O
Mg is oxidized as the oxidation number of Mg increases from 0 (in Mg) to +2 (in MgSO₄). Hence, Mg is the reducing agent.
H₂SO₄ is reduced as the oxidation number of S decreases from +6 (in H₂SO₄) to +4 (in SO₂). Hence, H₂SO₄ is the oxidizing agent.
For reduction potentials, refer to: http://www.chemeddl.org/services/moodle/media/QBank/GenChem/Tables/EStandardTable.htm
Mg²⁺ + 2e⁻ → Mg …… E° = -2.37 V
2H⁺ + SO₄²⁻ + 2e⁻ → SO₂ + 2H₂O …… E° = +0.2 V
Hence, Mg + 2H₂SO₄ → MgSO₄ + SO₂ + 2H₂O …… emf = (+0.2 V) - (-2.37 V) = +2.57 V
Mg is oxidized as the oxidation number of Mg increases from 0 (in Mg) to +2 (in MgSO₄). Hence, Mg is the reducing agent.
H₂SO₄ is reduced as the oxidation number of S decreases from +6 (in H₂SO₄) to +4 (in SO₂). Hence, H₂SO₄ is the oxidizing agent.
For reduction potentials, refer to: http://www.chemeddl.org/services/moodle/media/QBank/GenChem/Tables/EStandardTable.htm
Mg²⁺ + 2e⁻ → Mg …… E° = -2.37 V
2H⁺ + SO₄²⁻ + 2e⁻ → SO₂ + 2H₂O …… E° = +0.2 V
Hence, Mg + 2H₂SO₄ → MgSO₄ + SO₂ + 2H₂O …… emf = (+0.2 V) - (-2.37 V) = +2.57 V
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