Silicon Carbide (SiC) – Carborundum
Complete Theory + 25 Previous-Year/Expected MCQs (2020–2026)
Carborundum is chemically known as
- Silicon nitride
- Silicon carbide
- Boron carbide
- Aluminium carbide
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The reaction in Acheson process is
- SiO2 + 3C → SiC + 2CO
- Si + C → SiC
- SiO2 + 2C → Si + 2CO
- SiO2 + C → SiO + CO
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Silicon carbide has structure similar to
- Graphite
- NaCl
- Diamond
- CsCl
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Hardest material after diamond is
- SiC
- B4C
- cubic BN
- Corundum
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SiC is widely used in power electronics because of its
- Wide band gap & high thermal conductivity
- Narrow band gap
- Low breakdown voltage
- Low electron mobility
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Natural form of SiC is called
- Corundum
- Moissanite
- Carborundum
- Quartz
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The process used for manufacture of carborundum is
- Solvay
- Acheson
- Hall-Heroult
- Serpek
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Hybridisation of Si and C in SiC is
- sp
- sp²
- sp³
- sp³d
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SiC heating elements can be used up to
- 800 °C
- 1200 °C
- 1600 °C
- 2000 °C
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β-SiC has which crystal structure?
- Hexagonal
- Cubic (zinc blende)
- Wurtzite
- Rock salt
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Mohs hardness of carborundum is
- 9
- 9.5
- 10
- 8.5
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Silicon carbide is an example of
- Ionic solid
- Molecular solid
- Network covalent solid
- Metallic solid
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The reaction SiO2 + 3C → SiC + 2CO is an example of
- Oxidation
- Carbothermal reduction
- Aluminothermic reduction
- Self reduction
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Silicon carbide is chemically attacked by
- HCl
- HNO3
- Molten NaOH
- Dil. H2SO4
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Synthetic moissanite is used as
- Diamond simulant in jewellery
- Abrasive only
- LED only
- None
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SiC is used in EV inverters because it
- Reduces power loss significantly
- Increases weight
- Is cheaper than silicon
- Has low thermal conductivity
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Carborundum is used as
- Fertiliser
- Abrasive
- Flux
- Catalyst
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In silicon carbide, each silicon atom is surrounded by
- 4 carbon atoms
- 4 silicon atoms
- 6 carbon atoms
- 8 carbon atoms
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Silicon carbide is used in ceramic brake discs because of its
- High thermal conductivity & low density
- Low melting point
- High density
- Low hardness
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The colour of pure silicon carbide crystals is
- Colourless
- Black
- Greenish-blue iridescent
- Yellow
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Silicon carbide is prepared at temperature around
- 1000 °C
- 1500 °C
- 2200–2500 °C
- 3000 °C
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Carborundum is a
- Conductor
- Insulator
- Semiconductor
- Superconductor
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Which of the following is NOT a use of SiC?
- LED substrate
- Heating element
- Structural ceramic
- Superconducting magnet
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SiC is used in making bulletproof vests because it is
- Light & extremely hard
- Heavy & soft
- Flexible
- Conducting
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The bond in silicon carbide is predominantly
- Ionic
- Metallic
- Covalent
- Van der Waals
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Read also: Silicon Carbide: Preparation, Properties, Structure and Uses