Which reaction is a redox reaction?
1. HCI+H2O=H3O^+ +CI^-
2. H2SO4+2KOH=K2SO4+2H2O
3. CH4+2O2=CO2+2H2O
4. Fe^2+ +2OH^- =Fe(OH)2
I chose number 3, is this correct?
Yes, that is correct.
No, number 3 is not the correct answer. The correct answer is number 4. The reaction:
Fe^2+ +2OH^- =Fe(OH)2
is a redox reaction because the iron in Fe^2+ is oxidized from an oxidation state of +2 to +3 when it combines with hydroxide ions (OH^-) to form iron(II) hydroxide (Fe(OH)2). In this reaction, Fe^2+ is oxidized (loses electrons) and the hydroxide ions (OH^-) are reduced (gain electrons).
Yes, you are correct. Reaction number 3, CH4+2O2=CO2+2H2O, is a redox reaction.
To determine if a reaction is a redox reaction, you need to identify the changes in oxidation states of the elements in the reactants and products. In a redox reaction, at least one element undergoes an increase or decrease in its oxidation state.
In this reaction, the carbon atom in CH4 has an oxidation state of -4 (since hydrogen has an oxidation state of +1) and in CO2, it has an oxidation state of +4. This indicates that carbon is oxidized, as its oxidation state has increased from -4 to +4.
Similarly, oxygen in O2 has an oxidation state of 0, and in CO2 and H2O, its oxidation state is -2. This indicates that oxygen is reduced, as its oxidation state has decreased from 0 to -2.
Since reaction number 3 involves both oxidation and reduction processes, it is considered a redox reaction.