You still are having trouble with oxidation numbers.
a is not balanced. I think you meant to write
2SO2 + O2 ==> 2SO3
And that is a REDOX equation. S changes from +4 to +6; oxygen changes from zero (the O2 is zero while the O in SO2 is unchanged) to -2 in SO3.
b. You are correct that this is a redox equation but not for the right reasons. N changes from +4 in NO2 on the left to +5 in HNO3 on the right and +2 in NO on the right. Therefore, N in NO2 on the left undergoes both oxidation and reduction. You note that oxygen changes but it doesn't. The oxidation number on the left (in H2O) is -2 and on the right it is -2 in HNO3 and -2 in NO.
c. SO2(g) + H2O(l) �� H2SO3(aq)
S in SO2 is +4 and in H2SO3 is 4. No change. O in SO2 is -2 and O in H2O is -2. ON the right, O in H2SO3 is -2. No change so this is not a redox equation.
Re: your P.S. Because in MOST compounds, H is +1 and in MOST compounds O is -2. H is something other than +1 ONLY in the hydrides (LiH, NaH, KH, CaH2, etc where it is -1). O is other than -2 only in the peroxides (Na2O2, H2O2, K2O2, BaO2, etc where it is -1) AND in the superoxides (KO2, etc where it is -1/2).
Please help me verify:
The following reactions are involved in the formation of acid rain. Use oxidation numbers to identify which of these reactions are REDOX reactions.
a. 2SO2(g) + O2(g) �� 2SO2(g)
-2 -2 0 -2 -2
No change - not REDOX reacton
b. 3NO2(g) + H2O(l) �� 2HNO3(aq) + NO(g)
-3 -2 +1 -2 +1-3-2 -3-2
Nitrogen and Oxygen are reduced
REDOX reaction has occured
c. SO2(g) + H2O(l) �� H2SO3(aq)
-2-2 +1-2 +1-2-2
Oxygen is reduced
REDOX reaction has occured
Please check...
ps. why would they make a rule for hydrogen in most compounds being +1 when is it not? Same with oxygen being -2.
4 answers
Hi yes sorry the arrows didn't work out when I copied the question.
For the following in your answer
2SO2 + O2 ==> 2SO3
And that is a REDOX equation. S changes from +4 to +6; oxygen changes from zero (the O2 is zero while the O in SO2 is unchanged) to -2 in SO3.
Why is S +4? Doesn't S gain 2 electrons hence -2?
I'm using periodic table and S is in group 6A/16 . I thought 6A = 6
This is corrispondence course so all I have done is based on book explanation and my research so I'm not entirely confident on my periodic table use, maybe that is why I'm getting this wrong.
For the following in your answer
2SO2 + O2 ==> 2SO3
And that is a REDOX equation. S changes from +4 to +6; oxygen changes from zero (the O2 is zero while the O in SO2 is unchanged) to -2 in SO3.
Why is S +4? Doesn't S gain 2 electrons hence -2?
I'm using periodic table and S is in group 6A/16 . I thought 6A = 6
This is corrispondence course so all I have done is based on book explanation and my research so I'm not entirely confident on my periodic table use, maybe that is why I'm getting this wrong.
Hi again - was just comparing part c with your notes and I have an extra Oxygen on left side that right side doesn't have?? Perhaps your mistaken and oxygen is reduced?
Please disregard my 2 comments after. I finally had my Eureka moment and figured this all out. Thanks to your help and researching a bit more I feel I understand this now. Your efforts in helping me were not wasted lol. Thanks again!