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
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
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
Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in
A Coagulation and flocculation of colloids
B Oxidation of carbonaceous matter to CO2
C Nitrification or oxidation of ammonia derived from breakdown of nitrogeneous organic matter to the nitrite and eventually to the nitrate
D All of the above
Which of the following is caused by the higher concentration of Nitrogen and Phosphorous ?
A Eutrophication
B Hardness
C Alkalinity
D Acidity
If you travel along the Suez Canal from Port Said to Suez, you will come across several lakes. Which of the following lakes is not on this Canal?
A Great Bitter Lake
B Little Bitter Lake
C Lake Gatun
D Lake Timsah
Presence of phosphorous in metallurgical coal
A Is not undersirable
B Reduces its calorific value
C Badly affects the quality of steel
D Increases its caking power
Presence of high phosphorous in cast iron increases its
A Fluidity
B Melting point
C Shrinkage
D Tensile strength
The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by
A Biological oxygen pond
B Aerated lagoons
C Trickling filters
D Gravity separator having oil skimming devices

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