00:01
Okay, so we're going to balance the following redox reactions by the ion electron method.
00:11
Sorry.
00:13
So to do this, we're going to write out our whole equation, our cn minus plus mn -o -4 minus, yielding c -n -o -2.
00:21
Next, we have to know which one is being oxidated and which one is being reduced.
00:30
We also know that manganese has an oxidation number of 7 on the left side and 4 on the right.
00:39
You can get this from your periodic table.
00:43
So because it goes from plus 7 to plus 4, it is the one being reduced.
00:49
So we are going to take this one, the mn 04 from this side, and then the mno2 from this side, to create our half reaction.
01:00
The cn minus from the left and the cno minus from the right being our oxidized agents.
01:13
Next, we're going to have to treat these as individual reactions, and we're going to have to balance them.
01:20
Because it's in a basic solution, we need to add water and hydrogen.
01:27
Over here we need to make our we need to add rh2o so we're going to add some water here and because there's four oxygen over here we need our oxygen to be four on both sides so to do that we're going to add a two right here in front so now we've got four oxenogens on the left and four oxygens on the right next, we're going to balance the other side.
02:07
But we have to add our hydrogen here.
02:10
So we're going to go h plus.
02:15
And now we have to make sure our hydrogens are balanced.
02:18
So because we have four on this side, we're going to add a four right here.
02:27
Now that one is balanced.
02:31
Next we have to balance the charges.
02:33
Notice that there is no charge on the right side, but on the left side we do.
02:37
Do have four plus and one minus giving us three.
02:42
So we're going to add three electrons to this side, which is going to make the right or the left side a zero charge matching the right side.
02:59
Next we're going to go down to our oxidized reaction and we're going to balance the oxygen on the right side with adding water to the left side.
03:15
And then we're going to balance the other side by adding our hydrogen.
03:37
Now we have two hydrogen on the left and one on the right.
03:41
So let's go ahead and add a two right here.
03:44
Two hydrogens, carbon.
03:48
It looks like everything is balanced.
03:51
Now we need to balance the charges.
03:53
So over here we have a minus charge and over here we have a minus and a plus charge.
04:01
Or i'm sorry, on the right side we have plus two and a minus.
04:07
And then on the left side we have a minus.
04:10
So we're going to need to add two electrons to this side to get a minus one charge on both sides.
04:24
Now that we have both of those balance separately we have to remember that they are part they are one whole reaction so we have to make our electrons in both the redox or the oxidation and reduction equations the same so we have two over here and three over here so all we're going to do is take each of these and we have to make them equal so to do that, we're just going to swap this to and this three and multiply the whole equation.
05:05
So we're going to multiply this top one by the two, and we're going to multiply the bottom one by three.
05:16
Now we can actually see what's in our equation...
