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31.

The operating temperature and pressure in urea autoclave are

A.	550?C and 1000 atm respectively	B.	100?C and 1000 atm respectively
C.	185?C and 180 atm respectively	D.	25?C and 1 atm respectively

32.

Urea is formed in a low-pressure stripping operation by dehydration of

A.	ammonium bicarbonate	B.	ammonium carbomate
C.	biuret	D.	ammonium nitrate

33.

In the manufacture of urea from ammonia and carbon dioxide

A.	aluminium oxide is used as catalyst	B.	platinum is used as catalyst
C.	silica-alumina mixture is used as catalyst	D.	no catalyst is required

34.

Ammonium carbamate is formed by reacting ammonia and carbon dioxide at 180 atm and 185?C. The reaction is

A.	endothermic	B.	exthermic
C.	reversible	D.	catalytic

35.

Urea is formed by dehydration of ammonium carbomate in a lawpressure stripping operation. The reaction is

A.	reversible	B.	endothermic
C.	catalytic	D.	exothermic

36.

For given NH3/CO2 ratio temperature urea production rate

A.	decreases with increasing pressure	B.	increases with increasing pressure
C.	remains constant with change in pressure	D.	decreases linearly with increasing pressure

37.

For given NH3/CO2 ratio pressure (more than the dissociation pressure for the carbamate) urea production rate

A.	decreases with increase in temperature from 140?C to 175?C	B.	increases with increase in temperature to maximum at 175-180?C then falls off sharply
C.	decreases linearly with increase in temperature	D.	is independent of temperature

38.

For given pressure temperature and total feed rate urea yield

A.	increases with increase in NH3/CO2 ratio	B.	decreases with increase in NH3/CO2 ratio
C.	remains unaffected with change in NH3/CO2 ratio	D.	may increase decrease remains unaffected with change in NH3/CO2 ratio

39.

In the manufacture of urea biuret (NH2CONHCONH2) formation is kept at minimum (<1%) because

A.	it is an explosive	B.	it is a compound which is detrimental to germinating seeds and toxic to animals
C.	it decomposes urea into carbon dioxide nitrogen and water	D.	its nitrogen content is only 4 wt %

40.

Ammonium nitrate which is used as fertilizer contains about

A.	35% N	B.	25% N
C.	46% N	D.	82% N