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
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 | - |
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.
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 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 |
|
- |
| Reactivity with air | Does not react |
In this section, we are going see some reactions of ethanol why those reactions are important.
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.
Ethanol can be oxidized to ethanal (acetaldehyde) or ethanoic acid (acetic acid) or carbon dioxide by using suitable oxidizing agent.
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.
Though ethanol reacts with metallic sodium and potassium, it does not react with strong aqueous alkalis such as sodium hydroxide.
Ethanol partially dissociate in water. So ethanol shows weak acidic characteristics.
Questions
