Carborundum is used as an abrasive, because it

Carborundum is used as an abrasive, because it

has high thermal conductivity
has low coefficient of expansion
has high chemical stability
is extremely hard
This question was previously asked in
UPSC CAPF – 2017
The correct option is D.
Carborundum, also known as Silicon Carbide (SiC), is widely used as an abrasive primarily because it is extremely hard. Abrasive materials work by scratching or grinding away the surface of other materials, a process that requires the abrasive to be harder than the material being abraded. Carborundum is one of the hardest known materials, ranking high on the Mohs scale of hardness (around 9-9.5), making it effective for grinding and cutting hard substances.
While carborundum possesses other properties listed, such as high thermal conductivity (A) and high chemical stability (C), these properties are not the primary reason for its use as an abrasive. Low coefficient of expansion (B) contributes to its thermal shock resistance, useful in high-temperature applications, but is not the fundamental reason for its abrasiveness.