What Is Boiling Point? Everything You Need to Know!

Have you ever wondered what happens to water when it gets really hot? Or how pressure can affect the behavior of different substances?

You may have heard the term “boiling point” before, but do you know what it actually means?

In this blog post, we will dive into the concept of boiling point and explore its significance in various industries and everyday life.

Whether you’re a science enthusiast or simply curious about the world around you, this post will provide valuable insights into this fundamental concept. So, let’s get started!

What Is Boiling Point

Introduction Of  Boiling Point

The boiling point is a fundamental concept in thermodynamics and chemistry that plays a crucial role in various applications.

From cooking and food preparation to industrial processes, chemical reactions, and environmental science, the boiling point of a substance is a critical parameter that influences its behavior and utility.

Boiling Point Basics

Boiling point refers to the temperature at which a substance changes from its liquid state to its gaseous state, with the vapor pressure of the liquid becoming equal to the atmospheric pressure.

It is typically expressed in Celsius (°C) or Fahrenheit (°F) and varies depending on the substance being heated.

The boiling point is an intrinsic property of a substance and is determined by various factors, including atmospheric pressure, molecular weight and size of the substance, and intermolecular forces.

Atmospheric pressure has a significant impact on the boiling point of a substance. As atmospheric pressure decreases, such as at higher altitudes, the boiling point of a substance also decreases.

Conversely, as atmospheric pressure increases, such as in a pressurized container or under water, the boiling point of a substance increases.

This is why water boils at a lower temperature at high altitudes, where atmospheric pressure is lower, compared to at sea level where atmospheric pressure is higher.

The molecular weight and size of a substance also affect its boiling point.

Generally, substances with higher molecular weights and larger sizes have higher boiling points because they have stronger intermolecular forces that require more energy to overcome and transition from the liquid to the gaseous state.

For example, hydrocarbons with longer carbon chains in organic chemistry tend to have higher boiling points due to increased van der Waals forces between their molecules.

Intermolecular forces, such as hydrogen bonding, dipole-dipole interactions, and van der Waals forces, also play a crucial role in determining the boiling point of a substance.

Substances with stronger intermolecular forces generally have higher boiling points because more energy is required to break these forces and convert the substance into a gas.

For example, water (H2O) has a high boiling point of 100°C (212°F) due to its strong hydrogen bonding between water molecules.

Common Substances Boiling Point

Boiling point is an essential physical property of a substance that determines the temperature at which the substance changes its state from liquid to gas.

It is the temperature at which the vapor pressure of a liquid equals the atmospheric pressure.

The boiling point of a substance depends on several factors, including its molecular weight, intermolecular forces, and polarity. In this blog post, we will discuss the boiling points of some common substances.Water

Water is a vital substance that exists in all three states of matter in the earth’s environment.

It is a colorless, odorless, and tasteless liquid that boils at 100°C (212°F) at standard atmospheric pressure.

Water is a unique substance because its boiling point is higher than most other substances of similar molecular weight.

The reason for this is that water molecules are held together by hydrogen bonding, which requires a lot of energy to break the intermolecular forces. Therefore, water boils at a higher temperature than most other substances.

Substance Boiling Point (°C) Boiling Point (°F)
Water (H2O) 100 212
Ethanol (C2H5OH) 78.5 173.3
Benzene (C6H6) 80.1 176.2
Acetone (CH3COCH3) 56.2 133.2
Ammonia (NH3) -33.4 -28.1
Methane (CH4) -161.5 -258.7
Ethene (C2H4) -103.7 -154.7
Oxygen (O2) -183 -297
Nitrogen (N2) -195.8 -320.4

Please note that the boiling points of substances may vary depending on the pressure, and the values provided are at standard atmospheric pressure (1 atm). Different units (°C or °F) are also provided for convenience.

Common Elements Boiling Point

The boiling point of the elements increases from left to right across the periodic table, from the alkali metals to the noble gases.

The alkali metals, such as lithium and sodium, have low boiling points because they have weak metallic bonding between their atoms.

On the other hand, the noble gases, such as helium and neon, have high boiling points due to their strong intermolecular forces caused by their stable, closed-shell electron configuration.

Within a group, the boiling point of the elements increases from top to bottom.

This trend is because the higher elements in a group have more electrons, which results in stronger intermolecular forces.

For example, oxygen, located at the top of Group 16, is a gas at room temperature, whereas the heavier element, sulfur, located beneath it, is a solid at room temperature.

Element Symbol Boiling Point (°C) Boiling Point (°F)
Mercury Hg 356.7 674.1
Bromine Br 58.8 137.8
Chlorine Cl -34.04 -29.27
Phosphorus P 280 536
Sulfur S 444.6 832.3
Copper Cu 2567 4653.6
Sodium Na 883 1621.4
Potassium K 774 1425.2
Iodine I 184 363.2
Silicon Si 3265 5909

Please note that the boiling points of elements can vary depending on various factors such as pressure, purity, and isotopic composition.

The values provided are approximate values at standard atmospheric pressure (1 atm) and may be subject to slight variations.

Uses Of Boiling Point

The boiling point of substances has numerous applications in various fields. Here are some common uses of boiling point:

Cooking: The boiling point is crucial in culinary arts as it determines the temperature at which liquids such as water, milk, and oil reach their boiling point and start to vaporize.

This is utilized in cooking techniques like boiling, simmering, and steaming, which are essential for preparing a wide range of dishes.

Chemistry: In chemistry, the boiling point is a fundamental property used in the separation and purification of substances.

Techniques like distillation and fractional distillation utilize differences in boiling points to separate components of a mixture based on their volatility.

This is particularly useful in the production of chemicals, pharmaceuticals, and petrochemicals.

Industry: The boiling point is also utilized in various industrial processes such as refining, manufacturing, and production of materials.

For example, in the petroleum industry, the boiling point is used to separate crude oil into different fractions based on their boiling points to obtain products like gasoline, diesel, and jet fuel.

Environmental Science: The boiling point is used in environmental science to understand the vaporization and evaporation of substances in natural systems.

It is utilized in the study of the water cycle, air pollution, and volatile organic compounds (VOCs) in the atmosphere, which can have implications for climate change, air quality, and environmental health.

Pharmaceutical Industry: In the pharmaceutical industry, the boiling point is used in the production of medicines and drugs.

It is employed in processes such as formulation, extraction, and purification of active pharmaceutical ingredients (APIs) from natural sources or chemical synthesis.

Food Processing: The boiling point is utilized in food processing to sterilize, pasteurize, or cook food products. It is employed in canning, bottling, and other preservation techniques to ensure the safety and quality of processed foods.

Scientific Research: The boiling point is used in various scientific research fields such as material science, biochemistry, and physics.

It is employed in experiments, analyses, and simulations to understand the behavior of substances under different conditions and to develop new materials or technologies.

Automotive Industry: The boiling point is used in the automotive industry for the development of engine coolant and antifreeze.

The boiling point of these fluids is important in preventing overheating of the engine and maintaining optimal operating conditions.

Energy Industry: The boiling point is utilized in the production of energy, such as in power plants, where steam turbines are used to generate electricity.

The boiling point of water is crucial in the process of converting water into steam, which is then used to drive turbines and generate electricity.

Safety: The boiling point is also used in safety applications, such as in the design and operation of pressure vessels, boilers, and industrial equipment.

Understanding the boiling point is essential in preventing accidents related to overpressure or overheating of systems.

Measurement of Boiling Point

The boiling point of a substance can be measured using various methods, depending on the nature of the substance and the required accuracy of measurement.

Some common methods for measuring boiling points include simple distillation, fractional distillation, and ebulliometry.

Simple distillation is a common method used to determine the boiling point of a pure liquid.

It involves heating the liquid in a distillation flask, collecting the vapor in a condenser, and then measuring the temperature at which the vapor condenses back into a liquid.

The temperature at which the first drop of liquid condenses is considered as the boiling point of the substance.

Fractional distillation is a more advanced technique used to separate and determine the boiling points of different components in a mixture.

It involves repeated evaporation and condensation of the components based on their boiling points using a fractionating column, which allows for better separation of components with similar boiling points.

Ebulliometry is a precise method used to measure the boiling point of a liquid by determining the temperature at which the vapor pressure of the liquid is equal to the applied pressure.

This method is commonly used for high-boiling liquids or substances that decompose or react at their boiling points.

How To Measure Boiling Point 

Measuring the boiling point of a substance requires careful handling and following safety precautions to ensure accurate results and prevent any accidents.

Here are some steps on how to safely measure the boiling point:

Choose an appropriate setup: Use a proper setup that is designed for measuring boiling points, such as a distillation apparatus or a boiling point apparatus.

These setups typically consist of a round-bottom flask, a condenser, a thermometer, and a heat source. Make sure the setup is clean and in good working condition.

Use a well-ventilated area: Perform the boiling point measurement in a well-ventilated area or under a fume hood to prevent the accumulation of harmful vapors.

Avoid measuring the boiling point in a closed or confined space to prevent the risk of inhalation of hazardous fumes.

Wear appropriate protective equipment: Always wear appropriate personal protective equipment (PPE), including safety goggles, heat-resistant gloves, and a lab coat, to protect yourself from potential hazards associated with heat and chemicals.

Use a calibrated thermometer: Use a calibrated thermometer that is suitable for measuring the boiling point of the specific substance you are working with.

Make sure the thermometer is properly inserted into the setup and is not touching the bottom of the flask, as this can affect the accuracy of the measurement.

Control the heat source: Use a heat source that is appropriate for the substance you are measuring.

Avoid using an open flame or a heat source that is too powerful, as it can cause overheating and increase the risk of accidents.

Use a controlled and gradual heating process to reach the boiling point slowly and steadily.

Monitor the boiling process: Carefully monitor the boiling process as the temperature rises.

Once the substance starts boiling, observe the thermometer carefully and record the temperature at which the boiling point is reached. Take multiple readings to ensure accuracy.

Handle hot equipment with caution: After the boiling point measurement is complete, turn off the heat source and handle hot equipment with caution.

Use heat-resistant gloves or appropriate tools to handle hot glassware or other equipment to avoid burns or other injuries.

Dispose of hazardous substances properly: If the substance being measured has hazardous properties, dispose of it properly according to the relevant regulations and guidelines.

Do not dispose of hazardous substances down the drain or in regular trash.

Clean up the area: Clean up the area after the boiling point measurement is complete.

Dispose of any waste or used materials properly and clean the equipment thoroughly before storing it.

Follow standard laboratory procedures: Always follow standard laboratory procedures, including those related to handling chemicals, using equipment, and managing waste.

Adhere to the safety guidelines and recommendations provided by your institution or organization.


The boiling point is a significant property of substances that determines the temperature at which a substance changes from a liquid to a gas.

It is influenced by factors such as molecular weight, intermolecular forces, and atmospheric pressure.

Boiling points have practical applications in cooking, chemistry, and engineering, and understanding this concept is essential in various fields.