An azeotrope is a mixture of two or more liquids which displays the same level of concentration in liquid and vapor phase. Simple distillation can not alter Their proportions. These mixtures can either have a lower boiling point or a higher boiling point of the components.
They are termed as constant boiling mixtures as their composition remains unchanged by distillation. That is the constitutions stays in the same proportion even when the azeotrope is boiled. When distillation can not alter a fraction of a liquid, it results in azeotropes.
Types of Azeotropes
- Heterogeneous and Homogeneous Azeotropes
If azeotropes are found in constitutions of mixtures and if they are not completely miscible then they are termed as heterogeneous azeotropes. Homogeneous Azeotropes are azeotropes in which the constitutions of a mixture are miscible completely. Hetero Azeotropic distillation is comprised of two liquid phases.
- Positive Azeotropes
Azeotropic Mixture which has a higher boiling point than its constituents is termed as positive azeotropes. For instance consider a positive azeotrope, ethanol consisting of a concentration of around ninety-five percent and four percent of water in terms of weight. Water boils at hundred degree Celsius, and ethanol boils at around seventy-eight-degree Celsius, whereas azeotropes boil at around seventy-eight-degree Celsius indicating that it has a lower boiling point than its constituents.
- Negative Azeotropes
Azeotropic mixtures with less boiling point then its constitutions is termed as negative azeotropes. For instance consider a negative azeotrope, hydrochloric acid consisting a concentration of around twenty percent and seventy-nine percent of water in terms of weight. Water boils at hundred degree Celsius and hydrochloric acid boil at around minus eight four degree Celsius, whereas azeotropes boil at around seventy-eight degree Celsius indicating that it has a higher boiling point than its constituents.
- Binary Azeotropes
Binary Azeotropes are azeotropes consisting of two constitutions as mentioned above illustration. Ternary Azeotropes are azeotropes consisting of more than three constitutions.
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