Mixtures and their Separation Techniques

Pure water is not a mixture because it doesn’t contain impurities.

Ammonia (NH₃) is a compound made of two elements nitrogen and hydrogen chemically combined together in a fixed proportion by mass.

Soda water  is a homogeneous mixture of a gas in a liquid.

Blood is a colloidal solution, i.e. it is a heterogeneous mixture in which particle size is between 1–100 nm. Colloids are stable solutions as they do not settle down when kept undisturbed. Hence, solution ‘x’ can be blood. 

Both water and ammonia have fixed composition.

Air is a homogeneous mixture of many gases.

 Sugar is a compound and it is a property of compounds that they do not show the properties of their constituents.

Water is a compound made of two elements hydrogen and oxygen chemically combined in a fixed proportion mass. Sugar is also a compound and it has a fixed boiling point. Therefore, only option (3) is correct.

Since mixtures are made of more than one component, they do not have sharp melting and boiling points.

Water (H₂O), sugar (C₁₂H₂₂O₁₁) and salt (NaCl) are compounds as they are made of two or more elements chemically combined in a fixed ratio by mass. Therefore, they have definite compositions. Tea is a mixture of different compounds like water, sugar, milk, tea leaves, etc. and therefore, it has variable composition and there is no chemical bond between its components. Thus, tea is a mixture.

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.

True Solution is a homogeneous mixture of two or more substances in which substance dissolved (solute) in solvent has the particle size of less than 10^-9 m or 1 nm. Simple solution of salt in water is an example of true solution.

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.