Many people around the world consume alcohol after work, at parties, and in many other events. It is also used for the manufacturing of medicines and cooking purposes too. How many of you notice how much alcohol is left after cooking the dish.
There are many properties of alcohol that brings out many questions in mind. In this article, we will discuss whether alcohol evaporates or not.
So, does alcohol evaporate? Yes, alcohol does evaporate. It evaporates at a lower temperature than water. The molecule near the surface(liquid-gas boundary) tends to break hydrogen bonds and escape out of it. If we heat up alcohol mixed with water, the alcohol evaporates first due to the lower boiling point of alcohol.
The alcohol molecule exhibit the hydrogen bonding in its molecule the same as in water. Alcohol is an ingredient used in many beverages like beer, wine, whiskey but varies in proportion added to it.
If we talk about the chemical composition, it is an organic compound having a series of hydrocarbon attached with a hydroxyl group (-OH). This group is connected with carbon at one end of a series of hydrocarbons.
It is also expressed as R-OH where R is the series of hydrocarbons and OH is hydroxyl group connected. Basically, Ethanol or ethyl alcohol is alcohol that is used in common beverages that cause drunkenness.
The chemical formula of Ethanol is C2H5OH. If it is consumed in higher doses or on a daily basis, it can affect the liver badly and many other ill effects on the body.
However, if the consumption is limited or occasionally, It reduces anxiety. It slows down the nervous system and therefore the slower signaling makes the brain works slower.
Why alcohol evaporate?
Alcohol evaporates because of its vapor pressure and therefore, its molecule lying at the surface of alcohol (liquid-gas boundary) breaks its hydrogen bonding and tends to escape out of alcohol solution.
It should be noted that alcohol evaporates at a faster rate than water. If we add water to alcohol and start heating it for evaporating the mixture. We will analyze that alcohol evaporates leaving behind water because alcohol has a lesser boiling temperature than water.
the vapor pressure of C2H5OH(ethanol) is calculated around 5.95 kPa at temperature 20 degrees Celcius, and at a temperature of 63.5 degrees, its vapor pressure is calculated around 53.3 kPa.
We should understand the basic phenomenon of the evaporation process. The evaporation occurs when the vapor pressure at the surface of the alcohol solution is greater than the air above the surface of liquid due to which the molecules of liquid rapidly vibrate and escapes out of the liquid and converts into the gas molecule.
The alcohol molecules at the surface at some time acquire enough energy to break the molecular bonds and goes into the air in the form of vapors.
IMF (Intermolecular forces) are the forces that hold the molecule near each other in liquid and solid states. These are not chemical bonds force that keep the atom connected to each other. They are responsible for keeping the molecules near to each other.
The liquids that have less IMF value tends to vaporize more than the liquids having greater IMFs. Solid-state has greater IMFs than the liquids and gaseous state.
The liquids exhibit a vapor pressure that arises from the formation of vapor from a liquid molecule.
In the initial stage, this pressure increases as more number of molecules of the liquid turn to the gaseous molecule. When the liquid remains less, a decrease in vapor pressure is seen. And finally, an equilibrium point raches when the rate of vaporization and condensation becomes the same.
Factors that affect evaporation
There are many factors that are responsible for the rate of evaporation of a liquid solution, we will discuss them one by one. Below are the listed factors.
- Temperature: The rate of evaporation of a liquid solution is directly proportional to the temperature of the liquid.If a solution is subjected to a higher temperature, the molecules of liquid acquire higher kinetic energy than at normal room temperature, and molecules also gain enough energy required to break the bond.With higher temperatures, the intermolecular forces of liquid become weaker. As a result, the molecules tend to escape out more quickly. Therefore, as we increase temperature, the rate of evaporation becomes faster.More viscous fluids like honey, glycerine are comparatively viscous in nature than alcohol. These highly viscous fluids have greater intermolecular forces.
Heating them up also causes a reduction in their viscosity. Highly viscous liquids are less prone to evaporation. But with heating them, the rate of evaporation increases in such liquids.
- Surface area: The rate of evaporation is also dependent upon the surface area of the container containing a liquid solution. Like temperature, the rate of evaporation is directly proportional to the surface area.The larger surface area of liquid facilitates more molecules to accumulate over the surface. As we know, the molecules that are present on the surface will vaporize first.Therefore if the surface area will be larger, more molecules will get a chance to escape out of the liquid solution.
- Humidity: This is also an important factor that determines the rate of evaporation. Humidity is the measure of the number of water vapors present in the surrounding air.More the water vapors present in the air, the greater will be the humidity.The rate of evaporation decreases with the increase in humidity. If more liquid vapors will be present in the air, more is the possibility of their condensation making the evaporation slower.
Whereas more is the dryness in the air, more is the ease of liquid molecules in solution to vaporize in the air. Therefore, the rate of evaporation is inversely proportional to the humidity.
- Windspeed: As the movement of air around the surface of the liquid increases, the rate of evaporation also increases.This is because the escaped molecules of the liquid become gaseous molecules above the surface of the liquid and sometimes these gaseous molecules collide with liquid (liquid-air boundary) and again get converted into a liquid molecule.If the air movement swipes away these vaporized molecules, the likelihood of these vaporized molecules to get back to liquid molecules reduces.
Therefore, an increase in the speed of the wind increases the rate of evaporation.
Physical and Chemical properties of Alcohol
- Pure Ethanol is completely flammable on combustion
- Most alcohols are colorless. Flavors and colors are further added to give it a more impressive look.
- The density of alcohol is around 789 g/l that is lesser than that of water.
- One common property of alcohol is its solubility. It gets readily soluble in water because they both prefer hydrogen bonding due to the presence of a hydroxyl group (-OH).
- Alcohols having a smaller series of hydrocarbons are more soluble. As the length of hydrocarbon increases, the solubility decreases.
- They undergo reactions with active metals like sodium, potassium, etc that show their acidic nature. The hydroxyl group (-OH) attached to it makes it acidic.
- Ethanol alcohols have a higher boiling point of around 78 degrees Celcius/ 173.1 Fahrenheit because of strong hydrogen bonding.
- The boiling point of alcohol decreases with an increase in the branching of hydrocarbons. Primary alcohols possess a greater boiling point.
- Alcohols produce aldehydes and ketones through oxidation with the presence of an oxidation agent.
Uses of Alcohols
- Alcohol is widely used in pharmaceutical industries manufacturing medicines.
- Alcohol in 70 to 80 % concentration is used in the preparation of a disinfectant and hand sanitizer.
- It has also its use in making perfumes and paints.
- Ethanol is also used as a good solvent.
- One common use of it is in alcoholic beverages like beer, wine, whiskey, etc.
- It is also used in the automobile industry as a petrol additive for improving combustion in engines.
Alcohol does evaporate like other liquids. The molecules of alcohol present over the surface of it break the hydrogen bonding and escape out and turn out to vaporized molecules.
The liquids that have less IMF (intermolecular forces) tend to evaporate easily and faster than the liquids having comparatively larger intermolecular forces.
Like water and other liquids, the rate of evaporation of alcohol also depends on factors like temperature, surface area, humidity, and wind speed.
So, guys if you have any doubt, you can ask your question in the comment section. We will reach out to you as soon as possible.