The metal used for making radiations shield is
Pb
Fe
Zn
Si
Which one of the following statements regarding helium is incorrect?
It is used to fill gas balloons instead of hydrogen because it is lighter and non inflammable.
It is used as a cryogenic agent for carrying out experiment at low temperature.
It is used to produce and sustain powerful superconducting magnets.
It is used in gas cooled nuclear reactors.
In the alumino-thermite process, Al acts as
Flux
Oxidizing agent
Reducing agent
Promoter
Which one of the following is an amphoteric oxide?
Na2O
SO2
B2O3
ZnO
H3BO3 is
Monobasic and weak Lewis acid
Monobasic and weak Bronsted acid
Monobasic and strong Lewis acid
Tribasic and weak Bronsted acid
A hydride of nitrogen which is acidic is
NH3
N2H4
N2H2
N3H
Hydrogen will not reduce
heated cupric oxide
heated ferric oxide
heated stannic oxide
heated aluminium oxide
Graphite is a soft, solid lubricant,extremely difficult to melt. The reason for this anamolous behaviour is that, graphite
is an allotropic form of diamond
has molecules of variable molecular masses like polymers
has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak inter plate bonds
is a non-crystalline substance.
Carborundum is obtained when silica is heated at high temperature with
carbon
carbon monoxide
carbon dioxide
calcium carbonate
Which is not a mineral of aluminium?
Anhydrite
Bauxite
Corundum
Diaspore
