Ammonia, the starting material for urea, is manufactured by which process?
- A.Haber process
- B.Solvay process
- C.Contact process
- D.Ostwald process
Correct answer
Explanation
The correct answer is A, the Haber process. In it nitrogen from the air and hydrogen from natural gas combine directly over a finely divided iron catalyst at high pressure and a temperature of about 450 to 500 degrees Celsius; the ammonia produced is then reacted with carbon dioxide to make urea. Option B is wrong because the Solvay process manufactures sodium carbonate, the soda ash of glassmaking, from brine and limestone. Option C is wrong because the contact process makes sulphuric acid by oxidising sulphur dioxide over a vanadium pentoxide catalyst; that acid is what converts rock phosphate into superphosphate. Option D is wrong because the Ostwald process is the next step after Haber, oxidising ammonia to nitric acid, which is needed for ammonium nitrate and for explosives.
Read the full article: Industrial Chemistry: Glass, Cement, Fertilisers and PYQs
Practice Questions
View allWhich among the following is not a nitrogenous fertilizer?
- A.Ammonium Sulphate
- B.Calcium Cyanamide
- C.Superphosphate of Lime
- D.Urea
Show answer
Superphosphate of lime is made by treating rock phosphate with sulphuric acid, and the nutrient it supplies is phosphorus in the form of available phosphate, not nitrogen; it is therefore a phosphatic fertiliser.
Read the full explanation →What is a fertiliser that supplies two or more than two primary nutrients called?
- A.Straight fertiliser
- B.Organic manure
- C.Green manure
- D.Complex fertiliser
Show answer
Nitrogen, phosphorus and potassium are the three primary nutrients, and a fertiliser that carries two or more of them in one chemical compound is called a complex or mixed fertiliser; diammonium phosphate, which supplies both nitrogen and phosphate, and the NPK grades sold by number are the familiar examples.
Read the full explanation →What is the percentage of nitrogen present in farm yard manure (FYM) in general?
- A.0.5
- B.0.6
- C.0.8
- D.0.7
Show answer
Farmyard manure is the decomposed mixture of cattle dung, urine and bedding litter, and in general it carries only about half a per cent of nitrogen, along with roughly the same order of phosphate and potash.
Read the full explanation →Which substance is added to cement clinker during grinding to retard the setting of cement?
- A.Gypsum
- B.Fly ash
- C.Silica
- D.Alumina
Show answer
About two or three per cent of gypsum, which is calcium sulphate dihydrate, is ground with the clinker because it slows down the hydration of tricalcium aluminate, the compound that would otherwise set almost the moment water was added and leave no time to place the concrete.
Read the full explanation →The main raw materials used in the manufacture of Portland cement are:
- A.Limestone and clay
- B.Gypsum and sand
- C.Bauxite and coke
- D.Dolomite and graphite
Show answer
Cement needs one calcareous material, limestone, for its lime, and one argillaceous material, clay or shale, for its silica, alumina and iron oxide; the mixture is burnt in a rotary kiln at about 1450 degrees Celsius to give clinker, which is then ground with gypsum.
Read the full explanation →