Science One word answer.

Pure substance: Water, salt, sugar.
Mixture: Saltwater, soil, wood, air, cold drink, rubber, sponge, fog, milk, butter, clothes, food.

Tyndall effect is shown by colloidal solution. Here milk and starch solution are colloids therefore milk and starch solution will show Tyndall effect.

Among the following mixtures. 

2. Sea water.
   
3. Air.
   

5. Soda water.
   

We can check this by evaporating the given colourless liquid. If nothing is left behind then the colourless liquid is pure water.

This means that metals can be drawn into thin sheets and can also be drawn into wires.

Sublimation.

No, a solution cannot be heterogeneous. A solution is a homogenous mixture of two or more substances.

Sea-water and Soda-water.

Elements: Iron, Sulphur, Sodium and Carbon.
Compounds: Iron sulphide, Chalk, Washing Soda and Urea.

By evaporation we can separate the crystals from the liquid in China dish.

Butter can be separated from curd by centrifugation.

Dispersing medium and dispersed phase.

By filtration.

Sodium metal is soft and diamond is an extremely hard non-metal.

The path of light beam is illuminated and becomes visible.

Metals are malleable and ductile whereas non-metals are not.

Centrifugation method is used for separating suspended particles of substances from a liquid in which the mixture is rotated at high speed in a centrifuge.

Chromatography.

Fractional distillation of liquid air.

Paper chromatography.

Electromagnet.

Ductility.

Sublimation.

Physical change as there is no change in composition. Only the separation of components takes place by the physical phenomenon, centrifugation.

3. Assertion is true but the Reason is false.

Explanation:

Colloidal medicines are competitively more effective as they are easily absorbed by the body. That is way many medicines are emulsion. Some major antibiotics like penicillin and streptomycin are injected in the body in the form of colloidal sol so that they would be absorbed by the body easily.

Sodium.

Camphor can be separated from salt by sublimation.

A pure substance is one which is made up of only one kind of atoms or molecules.
Examples: Oxygen and sugar.

Unsaturated solution contains less solute at a given temperature and pressure.

This process is dissolution/ diffusion as potassium permanganate crystal is dissolved in water.

Ink, blood, foam.

Crystallization.

Filtration.

Centrifugation.

Mixture is another name for impure substances.
Examples: Milk and sea-water.

This process is sedimentation as sand does not dissolve completely in water and forms suspension and settles down at the bottom when left undisturbed for some time.

He should choose magnetic separation method to separate iron nails from saw-dust.

Kerosene and water. The mixture can be separated by using a separating funnel.

Colloid.

(b) milk and (d) starch solution show Tyndall effect because they are colloidal solution.
Whereas (a) salt solution and (c) copper sulphate solution are true solution. Their particle size is too small to scatter light. So they do not show Tyndall effect.

This is a experiment of separating dye from ink: Fill half a beaker with water and put a watch glass on the mouth of the beaker. Put few drops of ink on the watch glass. Now start heating the solution or mixture. after that the water evaporate continue heating till there is no further change in the watch glass. When the water is completely evaporated from the watch glass Dye is left in the watch glass.

This shows Tyndall effect, i.e., scattering of light by colloidal solution or by particles in a fine suspension. Dust particles are suspended in air which scatter the light coming from small hole.

Physical change as there occurs only the dissolution.

Carbon is a solid non-metal, bromine is a liquid non-metal and chlorine is a gaseous non-metal.

Hydrogen sulphide or H₂S has a smell of rotten eggs. H₂ or hydrogen does not have any odor.

Allotrope of carbon forms good conductor of electricity. That allotrope is graphite.

Crystallization is a process that separates a pure solid in the form of its crystals from a solution.
Crystallization is better than evaporation because during
Evaporation:

1. Some solids decompose or some, like sugar may get charred on heating to dryness.
2. Some impurities may remain dissolved in the solution even after.

Salt can be separated from sea-water by evaporation.

​​​Solution.

No this statement is not correct because all mixtures are not homogeneous. 
They are heterogeneous too. The appearance and composition of homogeneous mixtures are uniform throughout. 
Separate constituents are not identifiable in homogeneous mixtures whereas in heterogeneous mixtures separate substances can be easily observed.