Conditions for the reduction of dichromate by manganese(II) to chromium(III) [closed]








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> 
> The unbalanced redox reaction
> 
> 
> $$\ce{Mn^2+ + Cr2O7^2- -> Mn^3+ + Cr^3+}$$
> 
> 
> occurs in what type of condition?
> 
> 
> (**a**) Acidic  
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> (**b**) Basic  
> 
> (**c**) Neutral  
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> (**d**) Indeterminable
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> 
> 




$$\ce{Mn^{2+} + Cr2O7^{2-} -> Mn^{3+} + Cr^{3+}}$$


If you were to balance this reaction, using the appropriate molecules of water and protons, you'd get:


$$\ce{ Mn^{2+} + Cr2O7^{2-} + 14H+ + 5e- -> Mn^{3+} + 2Cr^{3+} + 7H2O }$$


The presence of protons the left side of equation suggests that this reaction has a higher rate when the concentration of protons is higher. That is, it is favored under acidic conditions.


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