posted by cassie .
What coefficient of H+ balances the atoms in the following half-reaction?
H^+ + MnO2 Mn^2+ + H2O
I think this is B...?
The arrow is between MnO2-->Mn^2+
each H gains zero electrons (from +1 to +1)
each O gains one electron(-1 to -2_
each Mn loses two electrons(+4 to +2)
so, if Mn loses two, and each O gains 1, it takes two O to absorb those electrons, so the coefficent of the H2O is 2, and the coefficent then of H+ is not B, but twice that.
Ya know - I originally thought D but someone else told me I was wrong...