Chemistry - Elements Their Occurrence and Extraction
Exam Duration: 45 Mins Total Questions : 30
In the froth floatation process for the purification of ores, the ore particles float because
- (a)
they are light
- (b)
their surface is not easily wetted by water
- (c)
they bear electrostatic charge
- (d)
they are insoluble
Which of the following types of metals is expected to occur in native state?
- (a)
Alkali metals
- (b)
Alkaline earth metals
- (c)
Noble metals
- (d)
Rare earth metals
Which one of the following metals occur chiefly as Oxide in nature?
- (a)
Zinc
- (b)
Aluminium
- (c)
Copper
- (d)
Lead
Carbon cannot be used in the reduction of Al2O3 because
- (a)
it is an expensive proposition
- (b)
the enthalpy of formation of CO2 is more than that of Al2O3
- (c)
pure carbon is not easily available
- (d)
the enthalpy of formatin of Al2O3 is too high
Which one of the following metals is extracted by aluminothermic process?
- (a)
Al
- (b)
Fe
- (c)
Cu
- (d)
Cr
The electrolytic reduction is employed in case of the extraction of
- (a)
Al
- (b)
Zn
- (c)
Cu
- (d)
Fe
The electrolytic method of refining is not suitable in extraction of
- (a)
Copper
- (b)
Zinc
- (c)
Aluminium
- (d)
Mercury
Which of the following metals occurs in the native or free state?
- (a)
Aluminium
- (b)
Sodium
- (c)
Calcium
- (d)
Gold
The most abundant metal in the earth's crust is
- (a)
Iron
- (b)
Copper
- (c)
Aluminium
- (d)
Sodium
In Zone refining method, the molten Zone
- (a)
consists of impurities only
- (b)
contains more impurity than one original metal
- (c)
contains the purified metal only
- (d)
moves to either side
Which one of the following is not a method of concentraction of metals?
- (a)
Gravity separation
- (b)
Froth floatation process
- (c)
Electromagnetic separation
- (d)
Smelting
Steel is
- (a)
an interstitial compound
- (b)
pure iron
- (c)
iron containing traces of Fe2O3
- (d)
iron containing traces of Cu
The substance Whish is added to ore in order to remove impurities during smelting is known as
- (a)
Slag
- (b)
Flux
- (c)
Gangue
- (d)
Catalyst
The reason for floating of ore particles in concentration by froth floatation process is their being
- (a)
light
- (b)
insoluble
- (c)
charged
- (d)
hydrophobic
In metallurgical processes the flux used for removing acidic inpurities is
- (a)
Silica
- (b)
Sodium chloride
- (c)
Lime stone
- (d)
Sodium carbonate
The main function of roasting is
- (a)
to remove the volatile matter
- (b)
oxidation of ore
- (c)
Both (a) and (b)
- (d)
to make slag
Which of the following metals is obtained by leaching its ore with dilute cyanide solution?
- (a)
Silver
- (b)
Titanium
- (c)
Vanadium
- (d)
Zinc
Electrolytic reduction method is used in the extraction of
- (a)
Highly electronegative elements
- (b)
Highly electropositive elements
- (c)
Transition metals
- (d)
Noble metals
In electrorefining of metal the pure metal is made the anode and a strip of pure metal the cathode during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of
- (a)
Silver
- (b)
Copper
- (c)
Aluminium
- (d)
Gold
Zone refining process is used for the
- (a)
Concentration of an ore
- (b)
Reduction of a metal oxide
- (c)
Purification of metal
- (d)
Purification of an ore
Which of the following metals cannot be extracted by smelting process?
- (a)
Pb
- (b)
Fe
- (c)
Zn
- (d)
Al
The extraction of which of the following metals involves bessemerisation?
- (a)
Fe
- (b)
Ag
- (c)
Al
- (d)
Cu
Which of the following benefication processes is used for the minerals Al2O3.2H2O?
- (a)
Froth flotation
- (b)
Leaching
- (c)
Liquation
- (d)
Magnetic separation
Among the following statements, the incorrect one is
- (a)
Calamine and sidherite are carbonates
- (b)
Argentite and cuprite are oxides
- (c)
Zinc blende and iron pyrites are sulphides
- (d)
Malachite and azorite are ores of copper
Which metal cannot be obtained from electrolysis?
- (a)
Ca
- (b)
Mg
- (c)
Cr
- (d)
Al
Which is the strongest reducing agent?
- (a)
Rb
- (b)
Na
- (c)
K
- (d)
Mg
The most abundant metal on the surface of the earth is
- (a)
Fe
- (b)
Al
- (c)
Ca
- (d)
Hg
The metal extracted by cyanide process is
- (a)
Silver
- (b)
Copper
- (c)
Iron
- (d)
Sodium
Malachite is an ore of
- (a)
Iron
- (b)
Zinc
- (c)
Copper
- (d)
Mercury
When the sample of copper with zinc impurity is to be purified by electrolysis, the appropriate electrodes are:
- (a)
CATHODE ANODE pure Zinc pure copper - (b)
CATHODE ANODE impure sample pure copper - (c)
CATHODE ANODE impure zinc impure sample - (d)
CATHODE ANODE pure copper impure sample