Permanganate ion is reduced to $M n O_{2}$ $MnO_2$ , and ammonia is oxidized to nitrate ion. Can you write a balanced chemical equation to represent the redox process?

Question

Permanganate ion is reduced to $M n O_{2}$ $MnO_2$ , and ammonia is oxidized to nitrate ion. Can you write a balanced chemical equation to represent the redox process?

1 Answer

Impact of this question

3438 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-04-22T05:19:43

This is a good one...............

Explanation:

You really have to make a meal out of these redox equations.

Permanganate ion (STRONGLY COLOURED PURPLE) could be reduced to almost colourless $M n^{2 +}$ $Mn^(2+)$ ....

${+ V I I M n O_{4}}^{-} + 8 H^{+} + 5 e^{-} \to M n^{2 +} + 4 H_{2} O$ $stackrel(+VII)[MnO_4]^(-) +8H^(+) + 5e^(-) rarr Mn^(2+) + 4H_2O$ $(i)$ $(i)$

But here it is reduced to $M n O_{2}$ $MnO_2$ .

${+ V I I M n O_{4}}^{-} + 4 H^{+} + 3 e^{-} \to {+ I V MnO}_{2} + 2 H_{2} O$ $stackrel(+VII)[MnO_4]^(-) +4H^(+) + 3e^(-) rarr stackrel(+IV)"MnO"_2 + 2H_2O$ $(i i)$ $(ii)$

Ammonia is OXIDIZED to nitrate anion.......(there is no associated colour change; ammonia pen and inks very badly, whereas ammonium ion/salt is odourless, but I do not suggest you use this method to differentiate them!)

${- I I I NH}_{3} + 3 H_{2} O \to {({+ V NO}_{3})}_{3}^{-} + 9 H^{+} + 8 e^{-}$ $stackrel(-III)"NH"_3 +3H_2O rarr (stackrel(+V)"NO"_3)^(-) +9H^(+)+ 8e^(-)$ $(i i i)$ $(iii)$

Now if I have done my sums right; $(i)$ $(i)$ , $(i i)$ $(ii)$ , and $(i i i)$ $(iii)$ ARE STOICHIOMETRICALLY BALANCED WITH RESPECT TO MASS AND CHARGE. If they are not, then they cannot be accepted as a representation of chemical reality. I think they are balanced, and so the final redox equation eliminates the electrons, and we take the sum........... $8 \times (i) + 5 \times (i i i)$ $8xx(i)+5xx(iii)$ :

$8MnO_4^(-) +5NH_3 + cancel(15H_2O) + cancel(64)19H^(+) rarr 8Mn^(2+) + 5NO_3^(-) +cancel(45H^(+))+ cancel(32)17H_2O$

And we cancel out common reagents to give (finally!):

$8MnO_4^(-) +5NH_3 +19H^(+) rarr 8Mn^(2+) + 5NO_3^(-) + 17H_2O$

Even despite the whack coefficients this is stoichiometrically balanced AS IS ABSOLUTELY REQUIRED...........

But you specified the reduction of permanganate to $MnO_2$ , so this is ........... $3xx(i)+5xx(iii)$ :

$8MnO_4^(-) +3NH_3 +5H^(+)rarr 8MnO_2(s) + 3NO_3^(-) +7H_2O$

But I note (well eventually I did!) that you specified BASIC conditions; all I have to do is add $5xxHO^-$ to each side of the equation............and eliminate the waters..........

$8MnO_4^(-) +3NH_3 rarr 8MnO_2(s) + 3NO_3^(-) +5HO^(-) + 2H_2O$

Manganese metal has a particularly rich redox chemistry. For another example of this redox manifold, see [here.](https://socratic.org/questions/standard-conditions-to-produce-k2mno4-3) See [here for redox reactions in general.](https://socratic.org/questions/can-you-explain-balancing-chemical-equations-in-detail#365584)

Science

Math

Humanities

... and beyond

Permanganate ion is reduced to $M n O_{2}$ $MnO_2$ , and ammonia is oxidized to nitrate ion. Can you write a balanced chemical equation to represent the redox process?

1 Answer

Explanation:

Related questions

Impact of this question

Science

Math

Humanities

... and beyond

Permanganate ion is reduced to MnO_2MnO2MnO_2, and ammonia is oxidized to nitrate ion. Can you write a balanced chemical equation to represent the redox process?

1 Answer

Explanation:

Related questions

Impact of this question

Permanganate ion is reduced to $M n O_{2}$ $MnO_2$ , and ammonia is oxidized to nitrate ion. Can you write a balanced chemical equation to represent the redox process?