Chapter 12, Problem 90A

Interpretation Introduction

Interpretation:

Boiling point of water and ethyl alcohol must be found at 1 atm from the given figure.

Also, the boiling point of water must be estimated at 0.8 atm pressure.

Concept introduction:

Boiling point of a liquid is the temperature at which vapor pressure of the liquid is equal to the atmospheric pressure.

Answer to Problem 90A

Boiling point of water at 1 atm is 100°C.

Boiling point of ethyl alcohol at 1 atm pressure is 78°C.

Boiling point of water at 0.8 atm is approximately 96°C.

Explanation of Solution

To get the boiling point the corresponding temperature must be found from the graph at which the vapor pressure is equal to the atmospheric pressure (760 torr).

The graph shows that vapor pressure reaches to 760 torr for water and ethyl alcohol at 100°C and 78°C respectively.

So boiling point of water and ethyl alcohol are 100°C and 78°C respectively.

Temperature corresponding to 0.8 atm (608 torr) is 96°C. Thus estimated boiling point of water at 0.8 atm is 96°C.

Conclusion

Boiling point of water and ethyl alcohol are 100°C and 78C respectively.

Estimated boiling point of water at 0.8 atm is 96°C.