Red Seal Boilermaker Practice Exam

How does the boiling point of water change under pressure?

1. The boiling point decreases as pressure increases

2. The boiling point remains constant regardless of pressure

3. The boiling point increases as pressure increases

4. The boiling point only changes under extreme pressures

The correct answer is: The boiling point increases as pressure increases

The boiling point of water is influenced by pressure due to the relationship between temperature and pressure as described by the principles of physical chemistry. When pressure increases, the boiling point of water also increases. This occurs because boiling happens when the vapor pressure of the liquid equals the surrounding atmospheric pressure. Under higher pressure conditions, more heat is required for the vapor pressure to reach that threshold, resulting in a higher boiling point. For example, in a pressure cooker, the pressure inside the pot is increased, which allows water to boil at temperatures higher than the normal boiling point of 100°C (212°F) at standard atmospheric pressure. This principle is essential in various boiling and heating applications, particularly in industrial settings where efficiency and safety are critical. Understanding this relationship plays a crucial role in boilermaking, as the safe handling of pressure vessels and systems is paramount to operating effectively and safely. Therefore, an increase in pressure correlates with an increase in the boiling point of water.