Chapter 9.2, Problem 32SSC

Interpretation Introduction

Interpretation:

The result of a double displacement reaction needs to be explained.

Concept introduction:

The type of replacement reaction in which exchange of ions takes place between two compounds of the reaction is known as double displacement reaction. One example of this type of reaction is,

${\text{Ca(OH)}}_2(aq)+2\text{HCl(}aq\text{)}\to {\text{CaCl}}_2(aq)+2{\text{H}}_{\text{2}}\text{O}$

Answer to Problem 32SSC

In a double displacement reaction, the formation of water, or precipitate or gas takes place.

Explanation of Solution

All double displacement reactions produce either water or a precipitate or a gas. The reaction between calcium hydroxide and hydrochloric acid produces water. A precipitate is produced in the reaction between sodium hydroxide and copper (II) chloride. An example of a double displacement reaction that forms a gas is that of potassium cyanide and hydrobromic acid.

$\text{KCN}\text{(}aq\text{)}\text{+}\text{HBr}\text{(}aq\text{)}\to \text{KBr}\text{(}aq\text{)}\text{+}\text{HCN}\text{(}g\text{)}$

Conclusion

Three products of the displacement reactions are water, precipitate and gas.