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

1 Answer
Jun 10, 2017

Answer:

#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.