In materials science and engineering, silicon carbide (SiC) is commonly used for which practical purpose because of its extreme hardness?

Introduction / Context:
Silicon carbide, with chemical formula SiC, is an important industrial material known for its exceptional hardness and thermal stability. General science questions often test whether students can link such well known materials to their major uses. Knowing the applications of SiC helps in understanding how different engineering materials are chosen for different tasks.

Given Data / Assumptions:

• The substance in question is silicon carbide (SiC).
• We are asked what it is commonly used for.
• Options include cement making, cutting hard substances, statue making, and disinfectant use.
• We assume school level knowledge of industrial materials and abrasives.

Concept / Approach:
Silicon carbide is an extremely hard material, ranking very high on hardness scales, just below diamond in many comparisons. Because of this property, it is widely used as an abrasive for cutting, grinding, and polishing extremely hard substances like metals, ceramics, and stones. It appears in grinding wheels, cutting tools, and sandpapers. It is not used as a disinfectant or as a main ingredient in ordinary cement paste, and while it can appear in advanced ceramics, making decorative statues is not its primary role in general knowledge contexts.

Step-by-Step Solution:
Step 1: Recall the key properties of silicon carbide, especially its great hardness and high melting point.Step 2: Match these properties with possible uses. Hard materials are ideal for abrasives and cutting tools.Step 3: Examine option B, which states cutting and grinding very hard substances as an abrasive, matching the expected application.Step 4: Consider option A, making cement paste, which usually uses compounds like calcium silicates, not silicon carbide.Step 5: Options C, D, and E do not align with the typical industrial role of SiC, so they can be rejected.

Verification / Alternative check:
Engineering and physics references list silicon carbide as a standard abrasive material in grinding wheels and cutting discs, particularly where high speed and high temperature performance are needed. Commercial abrasive papers often mention silicon carbide as the abrasive grain. These independent sources confirm that cutting and grinding hard materials is a major use of SiC.

Why Other Options Are Wrong:
Option A refers to cement paste, which primarily involves compounds of calcium, silicon, oxygen, and aluminium in forms like tricalcium silicate, not silicon carbide. Option C describes making statues, which is traditionally done from stone, wood, or metal; silicon carbide is too hard and expensive for that purpose. Option D, using it as a disinfectant, is scientifically incorrect because SiC is an inert ceramic, not an antimicrobial chemical. Option E mentioning table salt substitute has no basis in chemistry or practical use.

Common Pitfalls:
Students sometimes see the word silicon and think about construction materials like cement or glass, merging different silicon compounds in their minds. It is important to differentiate between silicon dioxide in glass, calcium silicates in cement, and silicon carbide as an abrasive. Remember that when a question highlights very hard substances, materials like diamond and silicon carbide should immediately be associated with cutting and grinding applications.

Final Answer:
Silicon carbide is widely used for Cutting and grinding very hard substances as an abrasive due to its extreme hardness.