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प्रश्न
An ore of manganese metal is:
(a) bauxite
(b) haematite
(c) cuprite
(d) pyrolusite
उत्तर
(d) Pyrolusite
Pyrolusite is an ore of manganese and the compound is manganese dioxide (MnO2).
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संबंधित प्रश्न
Define the Ore.
Why are the metals like Na, K, Ca and Mg never found in their free state in nature?
Name one metal which is extracted by reduction with aluminium.
Which of the following is an ore of mercury metal?
(a) rock salt
(b) cinnabar
(c) calamine
(d) haematite
Which of the following pair of metals exists in their native state in nature?
(a) Ag and Hg
(b) Ag and Zn
(c) Au and Hg
(d) Au and Ag
Give the principles of electromagnetic separation.
Give reasons, why aluminum is used in:
In aluminiothermy
Compare the process of calcination and roasting.
How many valence electrons are present in metals ?
The given reaction shows one of the processes to extract the metals like Iron and Manganese.
\[\ce{MnO2(s) + Al(s) -> Mn(l) + Al2O3(s) + Heat}\]
Give the reason why the above reaction is known as a thermite reaction.
