1) All of the following are oxidation-reduction reactions except
(a) 2Al(s) + Fe2O3(s) ---> A12O3(s) + 2Fe(s)
(b) (NH4)2Cr2O7(s) ---> Cr2O3(s) + N2(g) + H2O(1)
(c) Cu(s) + 2H2SO4(aq) ---> CuSO4(aq) + SO2(g) + 2H2O(1)
(d) Hg(NO3)2 + 4KI ---> K2HgI4(aq) +
2 KNO3(aq)
(e) 2Na(s) + 2H2O(1) --> 2NaOH(aq) +
H2(g)
This is a matter of going through each equation and determining the oxidation state of each, then comparing to see if any have changed. If not, that will answer your question.
1. Al is 0 on the left and +3 on the right. Therefore, this is an oxidation/reduction equation.
etc.
To determine which of the given reactions are oxidation-reduction reactions, we need to identify the changes in oxidation states of the elements involved.
An oxidation-reduction reaction, also known as a redox reaction, involves the transfer of electrons between species. In these reactions, certain elements undergo oxidation (increase in oxidation state) while others undergo reduction (decrease in oxidation state).
Let's examine each reaction:
(a) 2Al(s) + Fe2O3(s) ---> Al2O3(s) + 2Fe(s)
In this reaction, aluminum (Al) is oxidized from an oxidation state of 0 to +3, while iron (Fe) is reduced from +3 to 0. This is an oxidation-reduction reaction.
(b) (NH4)2Cr2O7(s) ---> Cr2O3(s) + N2(g) + H2O(1)
In this reaction, the nitrogen (N) in ammonium (NH4) is reduced from -3 to 0. Chromium (Cr) in chromate ions (Cr2O7) is reduced from +6 to +3. This is also an oxidation-reduction reaction.
(c) Cu(s) + 2H2SO4(aq) ---> CuSO4(aq) + SO2(g) + 2H2O(1)
In this reaction, copper (Cu) is oxidized from 0 to +2, while sulfur (S) in sulfuric acid (H2SO4) is reduced from +6 to +4. This is an oxidation-reduction reaction.
(d) Hg(NO3)2 + 4KI ---> K2HgI4(aq) + 2 KNO3(aq)
In this reaction, the oxidation states of mercury (Hg), iodine (I), and nitrogen (N) do not change. This is not an oxidation-reduction reaction.
(e) 2Na(s) + 2H2O(1) --> 2NaOH(aq) + H2(g)
In this reaction, sodium (Na) is oxidized from 0 to +1. Hydrogen (H) is reduced from +1 to 0. This is an oxidation-reduction reaction.
Therefore, the reactions that are NOT oxidation-reduction reactions are:
(d) Hg(NO3)2 + 4KI ---> K2HgI4(aq) + 2 KNO3(aq)
To determine this, we identified the changes in oxidation states for each element involved. Keep in mind that oxidation states may vary depending on the circumstances, so it is important to consider the reaction conditions and the rules for assigning oxidation states.
The oxidation-reduction reactions involve the transfer of electrons between substances. To determine which of the given reactions is not an oxidation-reduction reaction, we need to identify the reaction that does not involve the transfer of electrons.
(a) 2Al(s) + Fe2O3(s) ---> A12O3(s) + 2Fe(s)
This reaction involves the transfer of electrons, making it an oxidation-reduction reaction.
(b) (NH4)2Cr2O7(s) ---> Cr2O3(s) + N2(g) + H2O(1)
This reaction involves the transfer of electrons, making it an oxidation-reduction reaction.
(c) Cu(s) + 2H2SO4(aq) ---> CuSO4(aq) + SO2(g) + 2H2O(1)
This reaction involves the transfer of electrons, making it an oxidation-reduction reaction.
(d) Hg(NO3)2 + 4KI ---> K2HgI4(aq) + 2 KNO3(aq)
This reaction involves the transfer of electrons, making it an oxidation-reduction reaction.
(e) 2Na(s) + 2H2O(1) --> 2NaOH(aq) + H2(g)
This reaction does not involve the transfer of electrons. It is a displacement reaction where sodium (Na) displaces hydrogen (H) in water, and the products are formed without any electron transfer. Therefore, the answer is (e) 2Na(s) + 2H2O(1) --> 2NaOH(aq) + H2(g).