Chapter 2, Problem 64A

Interpretation Introduction

Interpretation: The colorless substance which is gas at $60{}^{\text{o}}\text{C}$ needs to be determined.

Concept Introduction: The melting point is defined as the temperature at which a solid substance starts melting. The boiling point is defined as the temperature of a liquid when its vapor pressure is equal to the atmospheric pressure. This is the temperature when liquid starts boiling and converts into vapor.

Answer to Problem 64A

Neon.

Explanation of Solution

From the given data, colorless substances are as follows:

Ethanol, neon, and water.

Here, the melting and boiling point of ethanol is $-117{}^{\text{o}}\text{C}$ and $78{}^{\text{o}}\text{C}$ respectively. Similarly, the melting point and boiling point of neon is $-249{}^{\text{o}}\text{C}$ and $-246{}^{\text{o}}\text{C}$ respectively. The melting point and boiling point of water is $0{}^{\text{o}}\text{C}$ and $100{}^{\text{o}}\text{C}$ respectively.

Here, water cannot be gas at $60{}^{\text{o}}\text{C}$ because it is liquid between temperatures $0-100{}^{\text{o}}\text{C}$ . It starts boiling at $100{}^{\text{o}}\text{C}$ ; thus, it is gas or vapor when the temperature is above ${\text{100 }}^{\text{o}}\text{C}$ . Now, ethanol is liquid and neon is gas at room temperature. The boiling point of ethanol is $78{}^{\text{o}}\text{C}$ ; thus, it will be gas when the temperature is above $78{}^{\text{o}}\text{C}$ . Similarly, the boiling point of neon is very low that is $-246{}^{\text{o}}\text{C}$ ; thus, it is gas at $60{}^{\text{o}}\text{C}$ .

Thus, the correct answer is neon.

Conclusion

Thus, neon is gas at $60{}^{\text{o}}\text{C}$ .