Which of the following statements about the reaction, 4 HCl(aq) + MnO2(s) MnCl2(aq) + 2 H2O(l) + 2 Cl2(g), is correct?
a.)The manganese atoms are oxidized. b.)The oxygen atoms are reduced. c.) The chlorine atoms are both oxidized and reduced. d.)All of these statements are INCORRECT.
So Here is the possibilities I ended up with.
4 HCl(aq) + MnO2(s) MnCl2(aq) + 2 H2O(l) + 2 Cl2(g)
H:+1 CL: -1 Mn:+4 O:-2 --> Mn:+2 Cl:-1 H:+1 O:-2 Cl:0
OR
H: 1 Cl: -1 Mn: +4 O:-2 Mn +4 Cl: -2 H:1 O: -2 Cl: 0
I tried to answer with Chlorine is being oxidized and reduced, but it was wrong. So how am I approaching this wrong? Cause for both it doesn't make sense as to where the electrons are coming from to balance out those charges for Manganese and Chlorine.
(H: +1, Cl: -1) (Mn: +4, O: -2)
-->
(Mn: +2, Cl: -1) (H: +1, O: -2)
(Cl: 0)
So, as you can see the Manganese atoms are clearly being reduced which means that it is gaining electrons, so the charge goes down. You can now eliminate choice A.
Next, we can see that the charge for oxygen does not change, so it is neither being reduced nor oxidized. You can now eliminate choice B.
Next, we can see that the charge on chlorine stayed the same in the HCl and the MnCl2. However, we must take into consideration the chlorine atoms which has a charge of 0. We can then say that the chlorine atoms were just oxidized because it lost electrons and the charge increased. Therefore, we can eliminate choice C.
The reason for this is because the chlorine atoms were only oxidized and not both.
In the end we are left with only choice D as the correct answer.
To determine which statements are correct about the given reaction, let's analyze the changes in oxidation states for each element:
We start with the reactants:
H: +1
Cl: -1
Mn: +4
O: -2
After the reaction:
Mn: +2
Cl: -1
H: +1
O: -2
Cl: 0
From the analysis, we can observe the following changes in oxidation states:
1. The oxidation state of manganese decreases from +4 to +2, indicating that it has been reduced. Therefore, statement a.) "The manganese atoms are oxidized" is incorrect.
2. The oxidation state of oxygen remains the same before and after the reaction. Thus, statement b.) "The oxygen atoms are reduced" is incorrect.
3. The oxidation state of chlorine changes from -1 (reactants) to -1 (products) and 0 (products). Since there is both an increase and a decrease in oxidation state for chlorine, statement c.) "The chlorine atoms are both oxidized and reduced" is incorrect.
Based on this analysis, we can conclude that statement d.) "All of these statements are INCORRECT" is correct.
Your incorrect approach was assuming that both the manganese and chlorine were being oxidized and reduced. However, in this reaction, only the chlorine does not have a consistent change in oxidation state.