Tag: preparation of ammonia-laboratory method and haber's process

Questions Related to preparation of ammonia-laboratory method and haber's process

Which gas is produced when calcium nitride $(Ca _{3}N _{2})$ is hydrolyzed by water?

  1. $N _{2}$

  2. $NH _{3}$

  3. $H _{2}$

  4. $O _{2}$


Correct Option: B
Explanation:
Ammonia gas is produced when calcium nitride $(Ca _{3}N _{2})$ is hydrolyzed by water.
$Ca _3N _2+6H _2O \to 3Ca(OH) _2+2NH _3$

Which of the following compounds will not give ammonia on heating?

  1. $(NH _{4}) _{2}SO _{4}$

  2. $(NH _{4}) _{2}CO _{3}$

  3. $NH _{4}NO _{2}$

  4. $NH _{4}Cl$


Correct Option: C
Explanation:

$NH _4NO _2$  will not give ammonia on heating.It gives $NO _2H _2O$

$NH _4NO _2(s)\rightarrow N _2(g) + 2H _2O(g)$

.

Hence option C is correct.

Which of the following factors would favour the formation of ammonia?

  1. High pressure

  2. Low temperature

  3. High volume

  4. Low pressure


Correct Option: A
Explanation:
According to Le Chatelier's principle, high pressure would favour the formation of $NH _{3}$
$N _{2}$(g) + 3$H _2${g) $\leftrightharpoons$ $NH _{3}$(g)
The optimum conditions for the production of $NH _{3}$ are pressure of 200 x 10$^{5}$ Pa (about 200 atm) and temperature of -700 K.
In the given reaction, the number of moles of reactant is more than the product and according to the ideal gas equation, the pressure is inversely proportional to the number of moles.
Thus, by increasing pressure i.e. at high pressure, the reaction will proceed in a forward direction towards less number of moles. Thus the formation of the ammonia increases.

In the preparation of $HNO _{3}$, we get NO gas by catalytic oxidation of ammonia. The moles of NO produced by the oxidation of two moles of $NH _{3}$ will be :

  1. 2

  2. 3

  3. 4

  4. 6


Correct Option: A
Explanation:
In the preparation of $HNO _{3}$, we get NO gas by catalytic oxidation of ammonia.In the below equation 4 moles of $NH _3$ produced 4 moles of $NO$.So the moles of $NO$ produced by the oxidation of two moles of $NH _{3}$ will be2 moles.
$4NH _3+5O _2\rightarrow 4NO+6H _2O$.
Hence option A is correct.

Ammonia is dried over :

  1. Quick lime

  2. Slaked lime

  3. Phosphorus pentoxide

  4. Con. $\mathrm{H} _{2}\mathrm{S}\mathrm{O} _{4}$


Correct Option: A
Explanation:

Ammonia is dried by passing it over quick lime because it is a basic gas. Ammonia cannot be dried by conc. sulphuric acid or phosphorus pentaoxide as they will form ammonium sulphate or ammonium phosphate with it.

An element X combines with hydrogen to form a compound $NH _3$. The element X is placed on the right side of the periodic table. What is true about the element X?
(a) Has $3$ valence electrons
(b) Is a metal and is solid
(c) Is a non-metal and is a gas
(d) Has $5$ valence electrons
(e) $NH _3$ reacts with water to form a basic compound.

  1. (a), (b) and (c)

  2. (b), (c) and (d)

  3. (c), (d) and (e)

  4. (e), (a) and (b)


Correct Option: C
Explanation:

X is N because it is placed on the right side of the periodic table & compound is $NH _3$. X is a non metal and valence electrons are $5$ & $NH _3+H _2O\rightarrow NH _4OH$(Base)

Ammonia can be collected by displacement of

  1. Water

  2. $Conc.{ H } _{ 2 }S{ O } _{ 4 }$

  3. Brine

  4. Mercury


Correct Option: D
Explanation:

Ammonia is an extremely soluble gas and cannot be collected by displacement of water or acid. It can only be collected over a liquid in which it does not dissolve. 

One such liquid is mercury because it does not react with ammonia and it can be easily collected by displacement of the metal as it is liquid at room temperature. 

Which of the following compounds do not give ammonia on reaction with water?

  1. ${ Mg } _{ 3 }{ N } _{ 2 }$

  2. $AlN$

  3. $CaC{ N } _{ 2 }$

  4. $Ca{ \left( CN \right) } _{ 2 }$


Correct Option: D

Urea is prepared by the chemical reaction of:

  1. acetamide and ethyl alcochol

  2. ammonium sulphate and calcium chloride

  3. ammonia and Carbon dioxide

  4. chlorine and water


Correct Option: C
Explanation:
The chemical formula of urea is $H _2N-CO-NH _2$
Urea is now prepared commercially in vast amounts from liquid ammonia and liquid carbon dioxide.

For the manufacture of ammonia by the reaction$N _{2}+3H _{2} \rightleftharpoons 2NH _{3}+21.9\ K cal$, the favorable conditions are:

  1. low temperature, low pressure & catalyst

  2. low temperature, high pressure & catalyst

  3. high temperature, low pressure & catalyst

  4. low temperature, high pressure 


Correct Option: B
Explanation:

The equation representing habers process of ${ NH } _{ 3 }$

synthesis is-${ N } _{ 2 }(g)+{ 3H } _{ 2 }(g)\rightleftharpoons { 2NH } _{ 3 }(g)\ $
pressure: 150-200 atm
temperature : $450℃-500℃$
catalyst : Iron