General Science Elements and Metals - General Knowledge Questions and Answers

21.

Galvanised iron sheets have a coating of

22.

Among the various allotropes of carbon,

A.	coke is the hardest, graphite is the softest
B.	हीरा है सबसे मुश्किल, कोक नर्म है
C.	हीरा है सबसे मुश्किल, ग्रेफाइट नर्म है
D.	हीरे की सबसे मुश्किल, दीपक काला नर्म है

23.

The group of metals Fe, Co, Ni may best called as

24.

Heavy water is

25.

The chemical (ethyl mercaptan) added to the otherwise odourless LPG cooking gas for imparting a detectable smell to the gas is a compound of