7 public questions tagged with this topic.
Simple distillation is used for liquids with boiling point differences > 25°C, like benzene (80°C) and toluene (110°C).
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Purification Methods - Crystallization Distillation Chromatography
Crystallization uses differential solubility (e.g., ethanol) to dissolve one solid and recrystallize it, leaving the insoluble one behind, ideal when melting points are irrelevant.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Purification Methods - Crystallization Distillation Chromatography
Crystallization relies on melting point or solubility differences, ineffective here. Chromatography exploits Rf differences, making it suitable.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Purification Methods - Crystallization Distillation Chromatography
Fractional distillation separates miscible liquids with boiling points differing by less than 25°C using a fractionating column.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Purification Methods - Crystallization Distillation Chromatography
Sublimation separates based on sublimation temperature differences, effective when solubility is identical but one solid sublimes and the other does not.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Purification Methods - Crystallization Distillation Chromatography
Differential extraction uses water to dissolve the soluble liquid (b.p. 100°C), separating it from the insoluble one (b.p. 120°C), leveraging solubility over boiling point difference.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Purification Methods - Crystallization Distillation Chromatography
Ion exchange selectivity depends on net surface charge of analyte at operating pH relative to matrix charge. For proteins, net charge is determined by relationship between buffer pH and isoelectric point pI. At pH above pI, protein is negatively charged and binds anion exchanger; below pI, it binds cation exchanger. Therefore stationary phase choice and pH optimization require consideration of pI, ensuring target molecule bears appropriate charge for binding while contaminants differ. Molecular mass influences gel filtration but not ion exchange, while solubility governs partition methods. Understanding pI-matrix relationship is essential for rational purification strategy and gradient elution design.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.
