# 4 - Redox Reactions and n factor Questions Answers Both are separate questions....How to know what reaction is going to occur in each?
Joshi sir comment

In first case reactions involved are

In second case reaction involved is${\mathrm{As}}_{4}{\mathrm{O}}_{6}+4{{\mathrm{I}}_{3}}^{-}\to {\mathrm{As}}_{4}{\mathrm{O}}_{10}+12{\mathrm{I}}^{-}$Now solve

inform if any issue

Balance

KMnO4+H2SO4+H2S -> K2SO4+MnSO4+S+H2O

Joshi sir comment

THE E0 VALUES OF FOLLOWING REDUCTn  Rxn  R GIVEN

Fe 3+ (aq ) + e ----> Fe3+ (aq)  E0= 0.771V

Fe2+(aq)  + 2e----> Fe (s) E0 =0.447V

WHAT WILL BE THE FREE ENERGY CHANGE FOR D Rxn ?

Fe3+(aq) + 3E----> Fe(s)

ans +11.87kJ/MOL.

Joshi sir comment

Third reaction is the sum of 1st and 2nd so energy of 3rd will be the sum of energies of 1st and 2nd.

delta G = n1FE1 + n2FE2 = 1F(0.771) + 2F(0.447) = F(0.771+0.894) = 1.665F = 1.665*96368 = 160452.7 J = 38203.03 cal = 38.20303 cal

so total energy of the reaction

Fe3+(aq) + 3e- -------> Fe(s) is 38.203 cal

and value of n = 3 so per mole energy = 38.203/3

oxide of E react with KOH & give compd like KMnO4 WHAT IS THE FORMULA OF OXIDE OF E

EO

E2O3

E2O7      OR ANY OTHER ANS (& IF ANY OTHER ONE THEN GIVE THAT ANS WITH SOLn)

Joshi sir comment

2 EO2 + 4 KOH + O2 → 2 K2EO4 + 2 H2O
and
3 K2EO4 + 2 CO2 → 2 KEO4 + 2 K2CO3 + EO2

so oxide will be EO2