Chapter 3.5, Problem 3.11CE

(a)

Interpretation Introduction

Interpretation:

Balanced equation has to be written and the substance that is oxidized, reduced, oxidizing agent and reducing agent has to be identified for the reaction given below.

    ${\text{Br}}_{\text{2}}(aq)+{\text{I}}^{-}(aq)\to$

Concept introduction:

Balanced equation:

Balanced equation is a chemical equation in which number of atoms for each element in the reaction and the total charge are same on both reactant side and the product side.

Steps in balancing the equation:

• Step 1: Write the unbalanced equation
• Step 2: Find the coefficient to balance the equation.
• The coefficient should be reduced to the smallest whole number.

The oxidation number of an element is zero. The oxidation number of a monoatomic ion equals its charge.

The oxidation number is zero for the summation of the oxidation numbers complete atoms in a complete formula.

The charge on the ion is equal to the summation of the oxidation numbers of complete atoms in poly atomic ion.

The oxidation state of alkali metal $(\text{Li, Na, K, Rb, Cs})$ is $+1$, and alkaline earth metal is $\text{(Be, Mg, Ca, Sr, Ba)}$ is $+2$.

The oxidation state of hydrogen is $+1$ (without bonding with metals), the oxidation state of oxygen is $-2$.

An oxidizing agent gains the electrons and is reduced in a chemical reaction and it is electron acceptor.

A reducing agent loses electrons and is oxidized in a chemical reaction and it is electron donor.

The oxidation state is called as oxidation number, which describes degree of oxidation (loss of electrons) of an atom in a chemical compound. Theoretically, the oxidation state is positive, negative or zero.

(b)

Interpretation Introduction

Interpretation:

Balanced equation has to be written and the substance that is oxidized, reduced, oxidizing agent and reducing agent has to be identified for the reaction given below.

    ${\text{Br}}_{\text{2}}(l)+\text{K}(s)\to$

Concept introduction:

Refer to part (a)