Question

A vendor sells white powdered salt mixed with white powdered stone. The knowledge of which property will help you detect this malpractice?
A.Ductility
B.Opacity
C.Density
D.Solubility

Answer 1

Hint: The vendor has mixed white powder salt and white powder stone, to detect this malpractice we need a method with the help of which we can separate both the compounds. This can be done based on differences in the physical and chemical properties of salt and stone.

Complete step by step answer:
The property due to which a solid material stretches under tensile strain is known as ductility. If metal is ductile it means by applying tensile strength it can be made into thin wire. This property cannot be employed to distinguish between the white powdered salt and the white powdered stone.
Opacity is a measure of impermeability of material to electromagnetic or other kinds of radiations, especially visible impermeability to visible light. This means a material with high opacity will not allow radiation to penetrate through it. This property too cannot be employed to differentiate between the two components of the mixture.
Density is the ratio of the mass and the volume of a material. Although it is different for stone and salt but to measure it in a mixture of both is not possible and since both the substances, salt, and stone powder are in powder form it will not be possible to distinguish between both based on their densities.
Solubility is defined as the maximum amount of a substance that will dissolve in the given quantity of a solvent at a specified temperature. Some substances like salts are highly soluble in water while others such as stone are not soluble in water. This property of salt and stone can be used to differentiate between them.
When the mixture of white powdered salt and white powdered stone is dissolved in water, the salt will get dissolved in water while the stone will remain undissolved. And thus the knowledge of solubility can be employed to detect the malpractice of the vendor.

So, the correct answer is Option D.

Note:
The malpractice of adding impurity to an edible substance is known as adulteration. Unfortunately, adulteration of some very vital and common food materials is prevalent in India. For example, adulteration of milk, salt, rice, etc. This is very harmful to children especially of growing age as the adulterant can cause serious damage to their body tissues leading to malnutrition, organ failure, and sometimes even death.