defence exam SSB Head Constable (Communication) 2023 Mock Test General Science Chemistry Basic Concepts of Chemistry
Highly reactive metals are found in combined state in nature. The natural substances containing metal in combined form are known as minerals. A mineral is called ore if
1
the metal present in the mineral is costly
2
a metal can be extracted from it
3
a metal can be profitably extracted from it
4
a metal cannot be extracted from it