Which of the following is an oxidation-reduction (redox) reaction?
A. 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)
B. 2NaN3(g) → 2Na(g) + 3N2(g)
C. 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
D. Fe(s) + Ni(NO3)2(aq) → Fe(NO3)2(aq) + Ni(s)
E. all of the above
buiun
Well, I could try cracking a joke about redox reactions, but I'm afraid it would fall a little flat... like the reduction half! 😄
In any case, the answer is E. All of the above are oxidation-reduction (redox) reactions.
The correct answer is E. all of the above.
Explanation:
A redox (oxidation-reduction) reaction involves a transfer of electrons. In all of the given reactions, there is a transfer of electrons:
A. 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)
In this reaction, the potassium (K) atoms lose electrons and are oxidized (K → K+), while the hydrogen (H2O) is reduced (H2O → H2).
B. 2NaN3(g) → 2Na(g) + 3N2(g)
In this reaction, sodium (Na) atoms lose electrons and are oxidized (Na → Na+), while nitrogen (N) atoms gain electrons and are reduced (N3 → N2).
C. 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
In this reaction, nitrogen (N) atoms lose electrons and are oxidized (N → NO), while oxygen (O2) atoms gain electrons and are reduced (O2 → H2O).
D. Fe(s) + Ni(NO3)2(aq) → Fe(NO3)2(aq) + Ni(s)
In this reaction, iron (Fe) atoms lose electrons and are oxidized (Fe → Fe2+), while nickel (Ni2+) ions gain electrons and are reduced (Ni2+ → Ni).
Thus, all of the given reactions involve a transfer of electrons and are examples of oxidation-reduction (redox) reactions.
To determine which of the given reactions is an oxidation-reduction (redox) reaction, you need to identify if there is a change in the oxidation states of the elements involved.
In an oxidation-reduction reaction, there is a transfer of electrons from one species to another. The species that loses electrons is oxidized, while the species that gains electrons is reduced.
Let's analyze each option:
A. 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)
In this reaction, the potassium (K) is oxidized as it goes from a neutral state (0 oxidation state) to a positive oxidation state in the KOH compound (+1). Hydrogen (H) in water is reduced as it changes from a positive oxidation state (+1) to a neutral state (0) in the form of H2. Therefore, Option A is an oxidation-reduction reaction (redox).
B. 2NaN3(g) → 2Na(g) + 3N2(g)
In this reaction, the sodium (Na) goes from a compound state in NaN3 to its elemental state (neutral state), meaning there is no change in oxidation state. The nitrogen (N) also doesn't change its oxidation state. Therefore, Option B is not an oxidation-reduction reaction (redox).
C. 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
In this reaction, nitrogen (N) goes from a neutral state (0 oxidation state) in NH3 to a positive oxidation state (+2) in NO. Oxygen (O) goes from a neutral state (0 oxidation state) to a negative oxidation state (-2) in water (H2O). Therefore, Option C is an oxidation-reduction reaction (redox).
D. Fe(s) + Ni(NO3)2(aq) → Fe(NO3)2(aq) + Ni(s)
In this reaction, iron (Fe) goes from its elemental state (neutral state) to a positive oxidation state in Fe(NO3)2 (+2). Nitrogen (N) in the nitrate ions of Ni(NO3)2 doesn't change its oxidation state. Nickel (Ni) also doesn't change its oxidation state. Therefore, Option D is an oxidation-reduction reaction (redox).
E. all of the above
Based on our analysis, Option B is not an oxidation-reduction (redox) reaction. Therefore, option E, "all of the above," is not correct.
In conclusion, the correct answer is: Option A, Option C, and Option D are oxidation-reduction (redox) reactions.