Which of the following is true concerning the reaction below?
H2S + HNO3 → S + NO + H2O
A. S is reduced.
B. H is oxidized.
C. N is reduced.
D. O is oxidized. ***
Oxidation is the loss of electrons.
Reduction is the gain or electrons.
S is -2 on the left and 0 on right.
H is +1 on the left and +1 on right.
O is -2 on the left and -2 on right.
N is +5 on the left and +2 on right.
The answer to this question is C. N is reduced
To determine which of the given options is true, we need to identify the elements and their oxidation states before and after the reaction.
In the given reaction: H2S + HNO3 → S + NO + H2O
The oxidation states in the reactants are:
- H2S: H is +1, S is -2
- HNO3: H is +1, N is +5, O is -2
The oxidation states in the products are:
- S: assume as 0 since elemental state
- NO: N is +2, O is -2
- H2O: H is +1, O is -2
Comparing the oxidation states, we can see that:
- The oxidation state of S changes from -2 to 0. Therefore, S is oxidized.
- The oxidation state of H changes from +1 to +1. Therefore, H is neither oxidized nor reduced.
- The oxidation state of N changes from +5 to +2. Therefore, N is reduced.
- The oxidation state of O changes from -2 to -2. Therefore, O is neither oxidized nor reduced.
Based on this analysis, the correct answer is:
C. N is reduced.
To determine which element is oxidized or reduced in a chemical reaction, you need to assign oxidation numbers to each element in the reaction. The oxidation number is a way to track the loss or gain of electrons by an atom.
In the reaction H2S + HNO3 → S + NO + H2O:
- Hydrogen (H) has an oxidation number of +1.
- Sulfur (S) in H2S has an oxidation number of -2.
- Oxygen (O) in HNO3 and H2O has an oxidation number of -2.
- Nitrogen (N) in HNO3 and NO has an oxidation number of +5.
Now, let's analyze the reaction:
H2S + HNO3 → S + NO + H2O
In this reaction, the oxidation state of sulfur (S) changes from -2 in H2S to 0 in S. This indicates that sulfur is gaining electrons and undergoing reduction. Thus, option A is not correct.
The oxidation state of hydrogen (H) remains at +1 throughout the reaction. Therefore, option B is not correct.
The oxidation state of nitrogen (N) changes from +5 in HNO3 to +2 in NO. This indicates that nitrogen is gaining electrons and undergoing reduction. Thus, option C is not correct.
The oxidation state of oxygen (O) changes from -2 in HNO3 to -2 in NO and H2O. The change in oxidation state for oxygen is zero, indicating that oxygen is neither oxidized nor reduced in this reaction. Thus, option D is the correct answer.
To summarize, option D is the correct choice because in the given reaction, oxygen (O) remains neither oxidized nor reduced.