Question

MnO4 - + SO2 = Mn2+ + SO42- balance the given redox reaction in acidic medium

Answer 1

2 (MnO4)- +5 SO2 +2 H20 = 5 (SO4)2- + 2 Mn2+ + 4 H+ 

Answer 2

Answer : The balanced redox reaction in acidic medium will be,

$2MnO_4^-+5SO_2+2H_2O\rightarrow 2Mn^{2+}+5SO_4^{2-}+4H^+$

Explanation :

In the half reaction method, the number of atoms in each half reaction and number of electrons should be balanced.

The half reactions in the acidic medium are :

$(1):MnO_4^-+8H^++5e^-\rightarrow Mn^{2+}+4H_2O\\\\(2):SO_2+2H_2O\rightarrow SO_4^{2-}+4H^++2e^-$

Now multiply the equation (1) by 2 and equation (2) by 5 and then added both equation, we get the balanced redox reaction.

Thus, the balanced redox reaction will be,

$2MnO_4^-+5SO_2+2H_2O\rightarrow 2Mn^{2+}+5SO_4^{2-}+4H^+$