Chapter 21, Problem 21.38P

(a)

Interpretation Introduction

Interpretation:

The balanced half reactions for the given redox process has to be identified.

Concept Introduction:

• Chemical equation is the representation of a chemical reaction, in which the reactants and products of the reactions are represented left and right side of an arrow respectively by using their respective chemical formulas.
• Reactant of a chemical reaction is the substrate compounds or the compounds which undergo a chemical reaction.
• Product of a chemical reaction is the produced compounds or the compounds formed after a chemical reaction.
• Balanced chemical equation of a reaction is written according to law of conservation of mass.
• Stoichiometry of a chemical reaction is the relation between reactants and products of the reaction and it is represented by the coefficients used for the reactants and products involved in the chemical equation.

(b)

Interpretation Introduction

Interpretation:

The $E^{\circ }{}_{cell}$ value for selenium has to be determined by using the $E^{\circ }{}_{cell}$ value of sulfite.

Concept Introduction:

An electrochemical cell is a device in which a redox reaction is used to convert chemical energy into electrical energy. Such device is also known as the galvanic or voltaic cell.

Galvanic cell consists of two half-cells. The redox reaction occurs in these half-cells. The half-cell in which the reduction reaction occurs is known as the reduction half-cell, whereas the half-cell in which the oxidation reaction occurs is known as the oxidation half-cell.

The standard cell potential for voltaic cell is determined by subtracting the electrode potential of cathode and the electrode potential of cathode.