Question

1. What is the strongest reducing agent?

Na

F^-

Fe^2+

Cd

Fe^3+

2. Balance the follow redox rxn. what are the coefficients in front of Cr & Cl2 in the balanced rxn?

Cr (s) + Cl2 (g) = Cr^3+ (aq) + Cl^- (aq)

3. Balance the follow redox rxn. what are the coefficients in front of Fe & Ag^+ in the balanced rxn?

Fe (s) + Ag^+ (aq) = Ag (s) + Fe^2+ (aq)

4. Balance the following redox rxn. What are the coefficients in front of Pb and H+?

Pb ^2+ (aq) + NH4 + (aq) = Pb (s) + NO3 - (aq)

Answer 1

The strengths of oxidizing and reducing agents are indicated by their standard electrode potentials.

Refer to standard electrode potentials,

In the given ions or elements Fe+2 is having highest standard electrode potential(negative sign shows it is favourable)

If Na was given in ionic form as Na+ could have been strongest , but it is given Na.

2. Cr + Cl2 ==> Cr⁺³+ Cl^-

Cr ==> Cr⁺³ + 3e

Cl2+ 2e​ ==> Cl^-

for balancing redox reaction we have to balance electrons in reactant and product in both oxidation and reduction half reactions.

We use cris-cross method generally

Hence, 3Cr + 2Cl2 ==> 3Cr⁺³ + 6Cl^-

coefficients are 3,2

3. Ag⁺+ e ==>Ag

Fe ==> Fe^+2​ + 2e

Here, by Cris-cross

Fe+2Ag⁺ ==> 2Ag + Fe⁺²

^{coefficient are 1,2}