An Acidic solution of KMnO4 is used to remove H2S from waste water. The Redox reaction forms sulphur and the purple solution turns colourless because of the formation of Mn²+.
How do i balance this redox reaction? If this is all the info i have.
Have you tried both Oxidation numbers and half-reactions to do it? If not, I’d recommend you do - my teacher would always throw one or two in that you could only balance with one method.
Frankly speaking i don even have any idea what the equation is suppose to look like. can anyone teach me how to arrive at an equation for this?
2KMnO[sub]4[/sub] + 3H[sub]2[/sub]S -----> 3S + 2MnO[sub]2[/sub] + 2H[sub]2[/sub]O + 2KOH
Nishroch,
You should try using www.google.com (or maybe you tried it already). Anyway, I asked it to find KMnO[sub]4[/sub] (exact phrase) and with the words H[sub]2[/sub]S.
Eventually I found out that Potassium Permanganate is used to remove Hydrogen Sulfide from Water.
I then found a page that told me what the products would be. (I had to balance the equation using an online equation balancer).
There is a LOT of stuff out there on the Internet.
Shameless plug for MY site — try using my site if you need help with schoolwork (particularly math problems).
Glad to help out.
thx wolf_meister :). so…with this “2KMnO4 + 3H2S -----> 3S + 2MnO2 + 2H2O + 2KOH” do i have to first balance it as an ionic equation before doing the redox?
Nishroch,
Again, I suggest going to www.google.com and look up oxidation reduction reactions ( or redox reactions ) and see what they have to say about balancing such equations.
The unbalanced equation is:
       **KMnO[sub]4[/sub] + H[sub]2[/sub]S -----> S + MnO[sub]2[/sub] + H[sub]2[/sub]O + KOH **
KMnO4 —> MnO2 + K+ + OH-
KMnO4 —> MnO2 + K+ + OH- + H2O
3e- + 3H+ + KMnO4 —> MnO2 + K+ + OH- + H2O
H2S----> S
H2S —> S + 2H+ + 2e-
6e- + 6H+ + 2KMnO4 —> 2MnO2 + 2K+ +2OH- + 2H20
3H2S—> 3S + 6H+ +6e-
2KMnO4 + 3H2S—> 2MnO2 + 2K+ + 2OH- + 2H2O + 3S
I Fucking Rock!
treis
Very good !!!
There was a limit to the amount of help I was going to provide Nishroch. I believe that moderators do not approve of people posting their homework just to get answers the easy way. (No I did not report this).
Now look what we’ve done. The original posting just had the reactants. Now we have given him the products, a balanced equation AND a method to balance the equation using half reactions.
I don’t know about you, but I refuse to go to school and take the test for him. LOL
Anyway, glad to help out Nishroch (remember you really should do some of this work on your own).
And good work treis !!!
Not to complicate things, but if the solution were alkaline (but you stated it was acidic), the reaction proceeds in a different manner.
haha thx treis. thx to wolf_meister too. Well, i wouldnt really consider this my homework just in case anyone is assuming. Just doing some revision on stuff i ought to already know years ago. thx for all the help ppl!
while we’re at it, H2S contains covalent bonds right? but why would it be this way?