JEE Main 2022 · 29 July · morning · Single correct · +4 / −1
In metallurgy the term "gangue" is used for :
- (a) Contamination of undesired earthy materials.
- (b) Contamination of metals, other than desired metal.
- (c) Minerals which are naturally occurring in pure form
- (d) Magnetic impurities in an ore.
Answer and solution
Answer (a) Contamination of undesired earthy materials.
Solution
Chemistry ma’am · 4 steps
Gangue is the earthy rubbish dug up with the ore: sand, rock and clay you must throw away.
- What an ore is. An ore is a mineral from which a metal can be extracted profitably. When it is mined, it never comes out alone.
- What comes with it. The ore is mixed with unwanted earthy material such as sand, rock, clay and silica (SiO₂). This unwanted earthy material is called gangue (or matrix).
- Why it matters. Gangue is removed during concentration of the ore, and whatever is left is removed later as slag with the help of a flux, for example CaO + SiO₂ → CaSiO₃.
- So. Gangue means contamination by undesired earthy materials, which is option (a).
The idea to keep. Gangue is the earthy, non-metallic junk mixed with an ore. Concentration removes most of it, and a flux turns the rest into slag.
Answer from the NTA final answer key. Solution by PrepWiser.