Chapter U6.2, Problem 2E

Interpretation Introduction

Interpretation: The indication of double arrow in a chemical equation needs to be explained.

Concept introduction: A reversible process in one that can proceed in both forward and the reverse direction. Many physical and chemical processes are reversible given the appropriate conditions.

Answer to Problem 2E

In a chemical equation, double arrow is used to show the reversible nature of reaction.

Explanation of Solution

Let’s take the following reaction,

  ${\text{H}}_{\text{2}}\text{O}\text{(}l\text{)}\rightleftharpoons {\text{H}}_{\text{2}}\text{O}\text{(}s\text{)}$

The reaction shows the phase change of water from liquid phase to solid phase (ice). Here, a double arrow is given which indicates that the reverse reaction will also occur, that is, phase change of solid phase of water (ice) to liquid phase of water by heating. Hence, the double arrow symbolizes the reversible reaction.

Conclusion

The double arrow indicates that both a forward and a reverse process can occur.