Question

what is the most essential condition that must be satisfied in Redox reaction

Answer 1

Determine the oxidation number of the elements in each of the following compounds:

a. H2CO3
H: +1, O: -2, C: +4

b. N2 
N: 0

c. Zn(OH)42- 
Zn: 2+, H: +1, O: -2

d. NO2- 
N: +3, O: -2

e. LiH 
Li: +1, H: -1

f. Fe3O4 
Fe: +8/3, O: -2


Identify the species being oxidized and reduced in each of the following reactions: 

a. Cr+ + Sn4+  Cr3+ + Sn2+ 
Cr+: oxidized, Sn4+: reduced

b. 3 Hg2+ + 2 Fe (s)  3 Hg2 + 2 Fe3+ 
Hg2+: reduced, Fe: oxidized

c. 2 As (s) + 3 Cl2 (g)  2 AsCl3 
As: oxidized, Cl2: reduced


Would you use an oxidizing agent or reducing agent in order for the following reactions to occur? 

a. ClO3-  ClO2   reducing agent

b. SO42-  S2-   reducing agent

c. Mn2+  MnO2   oxidizing agent

d. Zn  ZnCl2   oxidizing agent


Write balanced equations for the following redox reactions: 

a. 2 NaBr + Cl2  2 NaCl + Br2 

b. Fe2O3 + 3 CO  2 Fe + 3 CO2 in acidic solution 

c. 5 CO + I2O5  5 CO2 + I2 in basic solution 



Write balanced equations for the following reactions: 

a. Cr(OH)3 + Br2  CrO42- + Br- in basic solution

10 OH- + 2 Cr(OH)3 + 3 Br2  2 CrO42- + 8 H2O + 6 Br-
b. O2 + Sb  H2O2 + SbO2- in basic solution

2 OH- + 2 Sb + 3 O2 + 2 H2O  2 SbO2- + 3 H2O2
c. HCOOH + MnO4-  CO2 + Mn2+ in acidic solution

6 H+ + 2 MnO4- + 5 HCOOH  2 Mn2+ + 8 H2O + 5 CO2
d. ClO2-  ClO2 + Cl- in acidic solution

5 ClO2- + 4 H+  4 ClO2 + Cl- + 2 H2O


Write the balanced half reactions of the following reactions: 

a. NiO2 + 2 H2O + Fe  Ni(OH)2 + Fe(OH)2in basic solution 

2 H2O + NiO2 + 2 e-  Ni(OH)2 + 2 OH-

2 OH- + Fe  Fe(OH)2 + 2 e-

b. CO2 + 2 NH2OH  CO + N2 + 3 H2O in basic solution 

CO2 + H2O + 2 e-  CO + 2 OH-

2 OH- + 2 NH2OH  N2 + 2 e- + 4 H2O

c. 2 H+ + H2O2 + 2 Fe2+  2 Fe3+ + 2 H2O in acidic solution 

H2O2 + 2 e- + 2 H+  2 H2 O

Fe2+  Fe3+ + e-

d. H+ + 2 H2O + 2 MnO4- + 5 SO2  2 Mn2++ 5 HSO4- in acidic solution 

8 H+ + MnO4- + 5 e-  Mn2+ + 4 H2O

SO2 + 2 H2O  HSO4- + 3 H+ + 2 e- 

Answer 2

In a redox reaction, the total number of electrons lost by the reducing agent must be equal to the number of electrons gained by the oxidising agent.