Related Questions

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
The most stable allotropic form of phosphorous is the __________ phosphorous.
A White
B Black
C Yellow
D Red
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
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
Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes
A Foaming
B Odour nuisances
C Undesirable plant growth
D Turbidity
Presence of high phosphorous in cast iron increases its
A Fluidity
B Melting point
C Shrinkage
D Tensile strength
Quantity of coke produced from metallurgical coal may be around __________ percent.
A 30
B 50
C 75
D 95
Caking index of the coal blend used for the manufacture of metallurgical coke should be around
A 5
B 21
C 40
D 48
Higher percentage of ash in coal meant for the production of metallurgical grade coke
A Decreases the hardness of coke
B Decreases the abrasion resistance of coke
C Causes brittleness in steel
D None of these
Sulphur in metallurgical coal
A Contributes to its heating value
B Affects the quality of steel produced as cracks develop on the surface while rolling the steel
C Both A and B
D Neither A nor B

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