Related Questions

Red phosphorous is changed into white phosphorous by
A Heating in presence of light
B Melting under pressure
C Vaporisation followed by condensation
D None of these
The most stable allotropic form of phosphorous is the __________ phosphorous.
A White
B Black
C Yellow
D Red
Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at __________ °C in absence of air.
A 50-80
B 250-400
C 1000-1200
D 800-900
Both white phosphorous as well as red phosphorous
A Are soluble in CS2
B Burns when heated in air
C Reacts with hot caustic soda solution to give phosphine
D All of the above
In the blast furnace, incorporation of water vapour in the blast gives the following effect.
A Increases the reducing potential of the gas
B Increases the flame temperature
C No significant change occurs
D Increases the hydrogen content in the metal
Thermal efficiency of blast furnace stoves used for heating blast (air) may be about __________ percent.
A 20
B 40
C 60
D 80
Operation of blast furnace stove is based on the principles of a __________ furnace.
A Regenerative
B Recuperative
C Both A and B
D Neither A nor B
Electric furnace method for production of phosphorous uses phosphate rock
A And phosphoric acid
B And coke
C And sulphuric acid
D Silica and coke
Fusion zone in the electric furnace used for reduction of phosphate rock to elemental phosphorous is maintained at __________ °C.
A 250-300
B 500-750
C 950-1050
D 1400-1450
A mixture of phosphate rock __________ is heated in an electric furnace to produce phosphorous.
A Salt & coke
B Sand & coke
C And coke
D And sand

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