Physical and Chemical Properties of Ethanol (CH3CH2OH)

In chemistry and chemical engineering, ethanol is a commonly used as a laboratory chemical and industrial chemical because its hundreds of uses. To have these hundreds of uses, ethanol's physical and chemical properties are important and we will discuss about those in detail in this tutorial.

Content of the tutorial

  1. Physical properties of ethanol
  2. Applications of ethanol due to its specific physical properties
  3. Chemical properties of ethanol
  4. Applications of ethanol due to its specific chemical properties

Physical properties of ethanol

Physical properties with values of their measurable parameters are tabulated below. Units are also given with each parameter.

Physical property Value / Description Unit
Physical State at R.T Clear, colorless liquid -
Colour Colorless -
Odor Weak, ethereal, vinous odor -
Taste Burning -
Melting Point -114.1 0C
Boiling Point 78.2 0C
Flash Point 13 0C
Solubility in water 1000 mg cm-3
Density 0.79 g cm-3
Vapour Pressure at 250C 59.3 mm Hg
Viscosity at 25C 1.074 mPa.s
Surface tension at 250C 21.97 mN m-1
Heat of Evaporation at 250C 42.32 kJ mol-1
log P -0.18 -
Dipole moment 1.69 D -

Applications of ethanol due to its specific physical properties

Boiling point

Distillation of aqueous solution of ethanol: Ethanol production is done by the distillation of ethanol aqueous solution. Because boiling point of ethanol (78.20C) is less than water (1000C), we can use distillation to separate ethanol from water.

Solubility in water

Because ethanol can make hydrogen bonds with water molecules and ethanol's molar mass is not so much large, ethanol is highly soluble in water. Therefore, aqueous ethanol solutions can be prepared in different concentrations.

Chemical properties of ethanol

Chemical property Value / Description Unit
Heat of Combustion 1336.8 kJ mol-1
Heat of Formation -277.05 kJ mol-1
Reactivity with Water Very much soluble and weakly dissociates -
Products of Combustion
  • Complete combustion: CO2 and H2O
  • Incomplete combustion: CO can be given as a product with CO2 and H2O
Reactivity with air Does not react

Applications of ethanol due to its specific chemical properties

In this section, we are going see some reactions of ethanol why those reactions are important.

Acidity of ethanol

Ethanol is a very weak acid, But, it shows some acidic properties like some acids. Ethanol reacts with sodium and potassium (similar to acids and metals reaction) and emit hydrogen gas.

CH3CH2OH + O2 → CO2 + H2O

Oxidation of ethanol

Ethanol can be oxidized to ethanal (acetaldehyde) or ethanoic acid (acetic acid) or carbon dioxide by using suitable oxidizing agent.

  • In the presence of PCC, ethanol can be oxidized to ethanal (acetaldehyde).
  • If we use strong oxidizing agents such as acidic potassium permanganate or potassium dichromate, ethanol can be oxidized to ethanoic acid (acetic acid).
  • When ethanol is combusted with oxygen gas carbon dioxide and water are given as products.

Combustion of ethanol

Heat can be generated by the combustion of ethanol. Heat of combustion of ethanol is 1336.8 kJ mol-1.

When ethanol is burnt, sulfur dioxide or sulfur trioxide or nitrogen oxides are not given. Therefore, ethanol combustion is much more environmental friendly compared to than burning coal, diesel, petrol or any other sulfur and nitrogen containing petroleum fuels.

Combustion of ethanolPure ethanol liquid is highly flammable. Because ethanol is highly evaporative, ethanol vapour can catch fire. This is extremely dangerous incident if happened. As combustion products, carbon dioxide and water are given.

Reactivity with alkali metals and aqueous alkaline solutions

Though ethanol reacts with metallic sodium and potassium, it does not react with strong aqueous alkalis such as sodium hydroxide.

Dissociation of ethanol in water

Ethanol partially dissociate in water. So ethanol shows weak acidic characteristics.


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