Question

Alloys are prepared because-
A. Metals in their original state are unstable.
B. Individual metals are harmful.
C. Metal mixtures are cheaper than individual metals.
D. Metal mixtures show refined properties which are useful to mankind.

Answer 1

Hint: Alloys are the combination of two or more metal elements or metal and other elements. They are combined when they are in molten state. They are combined to produce elements of desired properties that are more useful than the pure metal. They are generally metallic in nature.

Step-by-Step Solution-
Alloys are homogeneous solid solutions which are prepared by mixing various metals in their molten state in required proportion and then they are cooled to room temperature.
In alloys the atoms of one metal are distributed randomly among the atoms of other element or metal. Alloys are generally formed by the atoms which have metallic radii within about $15\% $ of each other.
Alloys are prepared because they have following properties-
They are stronger and harder than the parent metals from which they are made.
They are less malleable and less ductile.
They are more corrosion resistant.
They have lower melting point and electrical conductivity.
They can be manipulated into different forms.
They are also more heat resistant.
One of the important alloys is steel, which is a mixture of iron and carbon and it is popular due to its low cost and high tensile strength. It is mainly used in construction of infrastructure and vehicles like trains and ships and also in electrical appliances.
Hence we can say that Alloys are prepared because they show refined properties which are useful to mankind .

Hence the correct answer is D.

Note: The importance of alloys is as follows-
- To reduce the price of the material and still maintain the desired properties of metal.
- To improve the properties of metal.
- To make the material oxidation resistant and provide mechanical strength