Sorting And Separation of Materials Test - 3

Pencil and ice have a lesser density than water, i.e. they are lighter than water.
Hence, they float in water.

Pencil, wooden table, notebook and bullock cart are classified together in group I as they are made up of wood/paper and are biodegradable; whereas bucket, polythene bag and chair are plastic products and are non-biodegradable, so they are classified together in group II.

Objects like wooden toy, plant leaf and plastic ball being less dense will float in water, whereas iron nail and stone will sink as they have a greater density than water.

Cardboard, chalk and wood are classified together in group I as they are not metallic materials.
However, copper wire, aluminium sheet, iron nail, steel rod and silver coin are classified together in group II as they are metallic objects.

Salt and sugar are water soluble substances as they completely dissolve in water to form true solutions. However, sand and chalk powder are insoluble in water and form a suspension when mixed with water and settle down if left undisturbed.

Materials can be classified into soluble or insoluble substances on the basis of their solubility in water or any other given solvent.
They may be grouped as conductors or insulators, on the basis of their conductivity.
They may be classified as transparent, translucent or opaque on the basis of transmission of light.
However, mass is not an appropriate property to classify the materials.

Statement 'b' is not correct as all metals do have a lusture, but it may not always be silvery white.
For example, gold has a yellow lusture and copper has a reddish brown lusture.
Iodine crystals have lusture and wood is a non-lustrous material. Hence, statements 'a' and 'c' are correct.

Salad is a typical example of a heterogeneous mixture.

The other statements are incorrect as all mixtures (homogeneous or heterogeneous) have a variable composition.
All the components in a homogeneous mixture are in the same phase.

True solution is a homogeneous mixture of two or more mutually inert substances.
The particles of the solute are less than 10^-9 m or 1 nm radius and impart the characteristic properties to the solution.
Simple solution of salt in water is an example of true solution.

Methane is a compound and is formed by the chemical combination of its elements in fixed proportions.

This is the correct answer because new substances formed exhibit completely different properties from their constituent elements.