Separation Techniques

Fractional distilation is used to separate two miscible liquids.

Sublimation (phase transition) is the change from solid to gas without entering liquid phase. Substances which undergo evaporation without going into liquid phase are purified by this method.

Chromatography is a technique for the separation of mixtures. The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at different speeds, causing them to separate. The separation is based on differential partitioning between the mobile and stationary phases. Subtle differences in partition coefficient of a compound result in differential retention on the stationary phase and thus, change in the separation.

Sublimation is the process of transition of a substance from solid phase to gas phase. Therefore, we can separate ammonium chloride from a mixture by using sublimation.

A mixture of water and kerosene oil can be separated by separating funnel.

Centrifugation technique is based on the principle that when a mixture is rotated at high speed, the lighter particles (less denser) stay on the surface of the liquid while the heavier particles (more denser) are forced to the bottom of the liquid. 

A cream separator uses rapid rotation to create centrifugal force, which pushes the denser components of milk (skim milk) outward, allowing the lighter fat (cream) to collect near the center.

NaCl (common salt) is not a sublime substance.

Alcoholic beverages contain alcohol, which is produced by the fermentation of glucose, and collected by fractional distillation.

During churning, milk undergoes circular motion, causing denser components to move outward while lighter fat particles, cream, collect near the center due to the centrifugal force. Centrifugal force acts outward in a rotating frame of reference, separating substances of different densities.

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Decantation is the laboratory process of separating a liquid from a solid sediment by carefully pouring the liquid out, leaving the solid behind. It relies on gravity to settle the particles.

This option is correct because number of replaceable hydroxyl ions present in one molecule of a base is called its acidity, is a true statement.

Coagulation is the process by which a colloid precipitates out of a solution. The precipitation is brought about by induced aggregation. Milk is a colloidal suspension in which the particles are prevented from aggregating because they have electric charges of the same sign. When milk sugar (lactose) ferments, ions responsible for curdling are formed.

The separation of an emulsion into its consistent liquids is called demulsification. The various methods used for demulsification are freezing, boiling, centrifugation, electrostatic precipitation or chemical methods which destroy the emulsifying agents.