CBSE
Multiple Choice QuestionsWhich of the following is not correct?
Al reacts with NaOH and liberate H2
AlCl3 is a Lewis acid
Al is used in the manufacture of electrical cables
NaOH is used during Hall's process of purification of bauxite
Lime stone is added in the extraction of lead from galena why?
It prevents the formation of PbSO4
It remove the impurity of silica as fusible slag
It converts lead silicate to lead oxide
All of the above
Bauxite is an ore of
boron
barium
aluminium
bismuth
Leaching is a process of
reduction
concentration
refining
oxidation
Flux is used to
remove all type of impurities
reduce metal oxide
remove carbonate and sulphate
remove silica and undesirable metal oxides
To dissolve argentite ore which of the following is used?
Na[Ag(CN)2]
NaCN
NaCl
HCl
The extraction of which of the following metals involves bessemerisation?
Fe
Ag
Al
Cu
Common alum is
K2SO4.Al2(SO4)3.24H2O
(NH4)2SO4.FeSO4.6H2O
K2SO4.Cr2(SO4)3.24H2O
K2SO4.Fe2(SO4)3.24H2O
In the extraction of copper from its sulphide ore, the metal is formed by reduction of Cu2O with:
CO
SO2
Cu2S
FeS
Which of the following statement is not correct?
A furnace lined with haematite is used to convert cast iron to wrought iron
Collectors enhance the muttability of mineral particles during froth floatation
In vapour phase retining metal should form a volatile compound
Copper from its low grades ores is extracted by hydrometallurgy
