To determine which element(s) are oxidized and reduced in the given redox reaction, we need to assign oxidation numbers to each element in the reactants and products.
First, let's assign oxidation numbers to all the elements:
In HNO, hydrogen (H) has an oxidation number of +1, nitrogen (N) has an oxidation number of +5, and oxygen (O) has an oxidation number of -2.
In HNO3, hydrogen (H) has an oxidation number of +1, nitrogen (N) has an oxidation number of +5, and oxygen (O) also has an oxidation number of -2.
In H2O, hydrogen (H) has an oxidation number of +1, and oxygen (O) also has an oxidation number of -2.
In 2NO, nitrogen (N) has an oxidation number of +2, and oxygen (O) has an oxidation number of -2.
Now, let's compare the oxidation numbers of each element in the reactants (left side of the arrow) and the products (right side of the arrow).
HNO (Reactant):
H: +1
N: +5
O: -2
HNO3 (Product):
H: +1
N: +5
O: -2
H2O (Product):
H: +1
O: -2
2NO (Product):
N: +2
O: -2
From the comparison, we can see that nitrogen (N) goes from an oxidation number of +5 in HNO to +2 in 2NO. This indicates that nitrogen has been reduced because its oxidation number has decreased.
On the other hand, hydrogen (H) and oxygen (O) do not change oxidation numbers, which means they are not oxidized or reduced.
To determine the total number of electrons gained or lost by each element, we need to look at the change in oxidation numbers:
Nitrogen (N):
Oxidation Number Change = Final Oxidation Number - Initial Oxidation Number
= +2 - +5
= -3
Since nitrogen (N) goes from an oxidation number of +5 to +2, it gains 3 electrons.
Hydrogen (H) and oxygen (O) do not change oxidation numbers, so they do not gain or lose any electrons.
Therefore, in the given redox reaction:
- Nitrogen (N) is reduced and gains 3 electrons.
- Hydrogen (H) and oxygen (O) do not undergo any oxidation or reduction and do not gain or lose any electrons.