When the redox equation Cr^(3+)(aq) + 3Mn(s) -> Mn^(2+)(aq) + Cr(s)Cr3+(aq)+3Mn(s)Mn2+(aq)+Cr(s) is completely balanced, what will the coefficient of Cr^(3+)(aq)Cr3+(aq) be?

1 Answer
Jun 10, 2017

2...........

Explanation:

Manganese is oxidized:

stackrel0Mn(s)rarrMn^(2+) + 2e^(-) (i)

Chromium is reduced:

Cr^(3+) + 3e^(-)rarrstackrel0Cr(s) (ii)

And so we take 3xx(i) + 2xx(ii) to eliminate the electrons:

3stackrel0Mn(s)+2Cr^(3+) rarr3Mn^(2+) + 2stackrel(0)Cr

Charge is balanced, and mass is balanced, and so this is a reasonable representation of reality. Whether the reaction actually works, I don't know, and cannot be bothered to look up redox tables.