Chapter U4.2, Problem 5E

Interpretation Introduction

Interpretation: The reactions between bleach and ammonia in solution are represented. The difference between given two reactions needs to be explained.

  ${\mathrm{NaOCl}}_{(aq)}+N{H}_{4}O{H}_{(aq)}\stackrel{}{\to }N{H}_{2}C{l}_{(g)}+NaO{H}_{(aq)}+H_2{O}_{(l)}$

  ${\text{NaOCl}}_{\text{(aq)}}{\text{ + 2NH}}_{\text{4}}{\text{OH}}_{\text{ (aq)}}\stackrel{}{\to }{\text{N}}_{\text{2}}{\text{H}}_{\text{4}}{}_{\text{(g)}}{\text{ + NaCl}}_{\text{(aq)}}{\text{+3H}}_{\text{2}}{\text{O}}_{\text{(l)}}$

Concept Introduction: A physical change is associated with change in the physical state of the substance whereas the chemical composition remains same.

A chemical change is associated with the change in the chemical composition of the substance. Chemical equation is the symbolic representation of a chemical change in which the chemical formula of the substances are written with their physical states.

Answer to Problem 5E

In the excess of ammonia; toxic chloramine will not form because reaction will lead to form hydrazine and sodium chloride as final product with water.

  ${\text{NaOCl}}_{\text{(aq)}}{\text{ + 2NH}}_{\text{4}}{\text{OH}}_{\text{ (aq)}}\stackrel{}{\to }{\text{N}}_{\text{2}}{\text{H}}_{\text{4}}{}_{\text{(g)}}{\text{ + NaCl}}_{\text{(aq)}}{\text{+3H}}_{\text{2}}{\text{O}}_{\text{(l)}}$

Explanation of Solution

Given information:

  ${\mathrm{NaOCl}}_{(aq)}+N{H}_{4}O{H}_{(aq)}\stackrel{}{\to }N{H}_{2}C{l}_{(g)}+NaO{H}_{(aq)}+H_2{O}_{(l)}$

  ${\text{NaOCl}}_{\text{(aq)}}{\text{ + 2NH}}_{\text{4}}{\text{OH}}_{\text{ (aq)}}\stackrel{}{\to }{\text{N}}_{\text{2}}{\text{H}}_{\text{4}}{}_{\text{(g)}}{\text{ + NaCl}}_{\text{(aq)}}{\text{+3H}}_{\text{2}}{\text{O}}_{\text{(l)}}$

The reaction between bleach and ammonia in solution can occur in two possible ways.

  ${\mathrm{NaOCl}}_{(aq)}+N{H}_{4}O{H}_{(aq)}\stackrel{}{\to }N{H}_{2}C{l}_{(g)}+NaO{H}_{(aq)}+H_2{O}_{(l)}$

In the limited quantity of ammonia solution, the reaction leads to the formation of poisonous chloramine with sodium hydroxide and water.

In the excess of ammonia; toxic chloramine will not form because reaction will lead to form hydrazine and sodium chloride as final product with water.

  ${\text{NaOCl}}_{\text{(aq)}}{\text{ + 2NH}}_{\text{4}}{\text{OH}}_{\text{ (aq)}}\stackrel{}{\to }{\text{N}}_{\text{2}}{\text{H}}_{\text{4}}{}_{\text{(g)}}{\text{ + NaCl}}_{\text{(aq)}}{\text{+3H}}_{\text{2}}{\text{O}}_{\text{(l)}}$

Conclusion

Thus, the quantity of ammonia effects the formation of product with bleach.