which o these equations are redox reactions? - 2Mg+ CO2 = 2MgO+ C - SiO2 + C = Si + CO2 - NaOH + HCl = NaCl + H2O -Fe + CuO= FeO + Cu?

2Mg + CO₂ → 2MgO + C is a redox reaction.

Oxidation number of Mg: 0 (in Mg) → +2 (in MgO) (increase)
Oxidation number of C: +4 (in CO₂) → 0 (in C) (decrease)
Oxidation number of O: -2 (in CO₂) → -2 (in MgO) (unchanged)

The reaction is redox because Mg is oxidized (increase in oxidation number of Mg) while CO₂ is reduced (decrease in oxidation number of C).


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SiO₂ + C → Si + CO₂ is a redox reaction.

Oxidation number of Si: +4 (in SiO₂) → 0 (in Si) (decrease)
Oxidation number of O: -2 (in SiO₂) → -2 (in CO₂) (unchanged)
Oxidation number of C: 0 (in C) → +4 (in CO₂) (increase)

The reaction is redox because C is oxidized (increase in oxidation number of C) while SiO₂ is reduced (decrease in oxidation number of Si).


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NaOH + HCl → NaCl + H₂O is NOT a redox reaction.

Oxidation number of Na: +1 (in NaOH) → +1 (in NaCl) (unchanged)
Oxidation number of O: -2 (in NaOH) → -2 (in H₂O) (unchanged)
Oxidation number of H: +1 (in NaOH and HCl) → +1 (in H₂O) (unchanged)
Oxidation number of Cl: -1 (in HCl) → -1 (in NaCl) (unchanged)

The reaction is NOT redox because there is no change in oxidation number.


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Fe + CuO→ FeO + Cu is a redox reaction

Oxidation number of Fe: 0 (in Fe) → +2 (in FeO) (increase)
Oxidation number of Cu: +2 (in CuO) → 0 (in Cu) (decrease)
Oxidation number of O: -2 (in NaOH) → -2 (in H₂O) (unchanged)

The reaction is redox because Fe is oxidized (increase in oxidation number of Fe) while CuO is reduced (decrease in oxidation number of Cu).

all except the acid-base neutralization (NaOH+HCl). It is really quite simple. a native element must change oxidation state to form a compound. Mg to MgO; Fe to FeO, C to CO2, Si to SiO2 (or the reverse).

Screw science ;D

I have honestly no idea