# Chemistry

I am having trouble with the balancing the oxidation-reduction equations that are in a basic solution.

This is the first one that I'm doing that's in a basic solution, and I can't get it! I get everything right except I get 2H2O instead of one on the left.

MnO4- + NO2- --> MnO2 + NO3-

Thank you!!

The method I use is longer than most but it has the advantage of also drilling students on oxidation state. But this method works.
1. Write the skeleton equation.
MnO4- ==> MnO2

2. Idendity the elements that changed oxidation state and place that number just above the element. Mn is +7 on the left and +4 on the right. I can't put those numbers on the ocmputer but you can on a sheet of paper.

3. Add electrons to the appropriate side to balance the change in oxidation state.
MnO4- + 3e==> MnO2

4. Count up the charge on both sides. I see -4 on the left and zero on the right. Now add OH^- to balance the charge.
MnO4- + 3e ==> MnO2 + 4 OH-

5. Now add water to balance the H atoms.
MnO4- + 3e + 2H2O ==> MnO2 + 4 OH-

6. Now check it for three things.
a. do the atoms balance? I see 1 Mn on the left and 1 on the right. There are 6 O on the left and 6 on the right. There are 4 H on the left and 4 on the right.

b. does the charge balance.
I see -4 on the left and -4 on the right.

c. Does the change in oxidatin state balance with the electrons that were added. Mn(+7) + 3e ==> Mn(+4). yes.

If it balances with a,b, and c, we were a success. I hope this helps. By the way, the procedure, except for a slight modification, works very well for acid solutions, too. On step 4, count up the charge and add H+ to balance. Everything else stays the same.

I guess it's obvious that I just balanced half of the equation. You must go through the NO3-==>NO2- part, make the electron change equal, and add the balanced half cells.

1. 👍 0
2. 👎 0
3. 👁 169

## Similar Questions

1. ### AP Chem

I'm having trouble balancing these two oxidation-reduction reactions that occur in a basic solution. Can anyone help? Please? The numbers after the formulas are subscripts and any with a minus sign means they are negatively

asked by rose on October 10, 2011
2. ### Chemistry

Dr.Bobb222 please help balance the following oxidation-reduction reactions, which occur in acidic solution, using the half-reaction method. (Use the lowest possible coefficients. Include states-of-matter under the given conditions

asked by Joanaleine Ferrera on January 29, 2016
3. ### Chemistry

I am pretty good at balancing oxidation reduction problems, but I can't do this one: HIO3 + FeI2 + HCL -> FeCl3 + ICl + HOH 5HIO3 + 4FeI2 + 25HCl -> 4FeCl3 + 13ICl + 15HOH I separated the three redox equations, added the two

asked by Brendan on February 2, 2007
4. ### Chemistry

The two most common oxidation states are Cr(III) and Cr(VI). Balance the following oxidation-reduction equations that involve one of these oxidation states of chromium. Assume that the reactions occur in acidic solution. A. Cr(s)

asked by Anonymous on February 24, 2016
5. ### General Chemistry

Balance the following redox reaction in acidic and basic solutions: Fe(OH)2(s) + O2(g) --> Fe(OH)3(s) These are the steps my instructor gave us to balance redox reactions: 1. Divide into 1/2 rxns (reduction & oxidation) 2. Balance

asked by Emily on April 3, 2013
6. ### Chemistry

Electron Transfer Theory Write an label the oxidation and reduction half-reaction equations. a) Ni(s) + Cu(NO3)2(aq) -> Cu(s)+ Ni(No3)2(aq) oxidation - Ni(s) -> Ni2+(aq) + 2e- reduction - Cu2+(aq) + 2e- -> Cu(s) b) Pb(s) +

asked by Alex on February 10, 2008
7. ### Chemistry

Electron Transfer Theory Write an label the oxidation and reduction half-reaction equations. a) Ni(s) + Cu(NO3)2(aq) -> Cu(s)+ Ni(No3)2(aq) oxidation - Ni(s) -> Ni2+(aq) + 2e- reduction - Cu2+(aq) + 2e- -> Cu(s) b) Pb(s) +

asked by Alex on February 10, 2008
8. ### AP Chemistry

2 Al + 3 Cu(NO3)2 --> 2 Al(NO3)3 + 3 Cu 1. Write balanced equations for the oxidation and reduction half-reactions. Identify each half-reaction as oxidation or reduction. 2. In the balanced overall reaction, determine which is the

asked by Neha on June 24, 2011
9. ### analytical chemistry

Write balanced net-ionic equations to describe: a. The oxidation of Mn2+ to MnO4- by ammonium peroxydisulfate [(NH4)2S2O8] b. The air-oxidation of HAsO32- to HAsO42- c. The oxidation of Ce3+ to Ce4+ by sodium bismuthate (NaBiO3)

asked by Anonymous on February 14, 2013
10. ### Chemistry- Dr Bob

Dr Bob Can you please assist Redox balancing in BASIC sol. NO2- +Al-->NH3 +Al(OH)4- if you could please walk through step by step. I don't know how to get oxidation #s for Al(OH)4- vs. Al I get Al=0 Al(OH)4-= +3 But if so...then

asked by Steve on June 7, 2013

More Similar Questions