JKSSB Written 2022
Answer & Explanation
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Correct Answer:
Option A —
It has lower calorific value than wood
In reality, charcoal has a higher calorific value than wood. Calorific value refers to the amount of heat energy released during the complete combustion of a unit mass of fuel. Charcoal is produced through the pyrolysis (heating in the absence of oxygen) of wood, which removes water and volatile compounds, leaving behind a concentrated carbon residue that burns hotter and cleaner.Analysis of the Options
A) Incorrect Statement: Wood generally has a calorific value of approximately 17–20 MJ/kg, whereas charcoal ranges between 28–33 MJ/kg. Therefore, charcoal is a much more efficient fuel.
B) Solid Amorphous State: Carbon in charcoal does not have a crystalline structure like diamond or graphite; it is an amorphous (non-crystalline) allotrope of carbon.
C) Low-density Compound: Charcoal is highly porous. Even though carbon itself is dense, the structural voids left behind after the removal of moisture and gases make charcoal light enough to float on water.
D) Good Absorbent: Due to its highly porous nature, charcoal (especially "activated" charcoal) has a massive surface area. This allows it to act as an excellent adsorbent, trapping gases, toxins, and impurities on its surface.
Answer verified by Quintessence Classes faculty — Karan Nagar, Srinagar.