Chapter U6, Problem 5STP

Interpretation Introduction

Interpretation:

The reversible process should be identified.

Concept introduction:

The process is said to be reversible in nature if the system and surroundings can be returned to its original conditions from final state. During this process, no changes is observed in thermodynamic properties.

Answer to Problem 5STP

The correct option is (c), water freezing to become ice.

Explanation of Solution

Reason for correct option:

Water freezing to become ice is a reversible process in which the state of matter changes from liquid to solid and the composition of substance remains same that is ${\text{H}}_{\text{2}}\text{O}$. If the ice is left for sometime at room temperature, then it regains its original form that is liquid state of water.

Hence, the correct option is (c), water freezing to become ice.

Conclusion

Reason for incorrect options:

Lighting a safety match and burning a log on fire:

It is an irreversible process that means once the safety match is lighten up or a log is burned on fire then it cannot be returned to its original conditions from final state as the combustion reaction takes place and forms products having different chemical compositions in comparison to the starting materials.

Baking a cake:

It is an irreversible process that means once the ingredients are mixed up for the cake and baked then it cannot be returned to its original conditions from final state.