Refractory materials are generally used in furnaces because
A. They pass great structural high strength
B. They can withstand high temperature
C. They are chemically inert
D. They do not require replacement

Hint: Refractory materials are the kind of material that is resistant to decomposition by pressure, heat, and chemical attack. These materials are used mainly in reactors, incinerators, and kilns. They are chemically inert and expand as well as contract uniformly.

Complete Step by Step Answer:
Refractory materials are non-metallic materials, having certain chemical and physical properties which make them applicable for structures as components of the system, which are exposed to the environments above ${{1000}^{{\mathrm O}}}F$.

An ideal refractory will consist of the following characteristic properties:
a. An ideal refractory material should be infusible at the operating temperature.
b. Should withstand the overlying load of large structures at the operating high temperature.
c. It should have good corrosion, heat, and abrasion resistance.
d. Should contract and expand uniformly with fall and rise of temperatures.
e. Should be good heat conductors for effective heat transmission in furnace construction.
For example, silica($Si{{O}_{2}}$), alumina($A{{l}_{2}}{{O}_{3}}$), magnesite, dolomite, zirconia, etc. are used as refractory materials.

These materials are generally used in furnaces as ceramic materials and can withstand very high temperatures. Also, they have an abrasive and corrosive nature. They can tolerate a huge temperature without deforming their shape.

Therefore, refractory materials are used in furnaces because they can withstand high temperatures instead of melting and becoming soft.
Thus, option (B) is correct.

Note: Refractive materials have a very important role in the cost and quality of steel products. The diversification of the products of steel and their cleanliness requirement in recent years has increased the demand for very high-quality refractory materials.