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Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

The wrong statements about $\displaystyle NH _{3}$ is :

  1. it is oxidised with oxygen at $\displaystyle 700^{\circ}C$ in the presence of platinum

  2. it gives black precipitate with calomel
  3. it can be dried by $\displaystyle P _{2}O _{5},\ H _{2}SO _{4}\, $and$\, CaCl _{2}$

  4. it gives white fumes with HCI
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
$NH _3$ is oxidised to nitric oxide and water with oxygen at $700^oC $ in the presence of platinum.
Aqueous ammonia reacts with calomel $Hg _2Cl _2$ to produce metallic mercury, a black precipitate. 
$CaO$ calcium oxide is used for drying of ammonia. Because $CaO$ being basic in nature does not react with $NH _3$ while $P _2O _5, $ conc. $H _2SO _4 \ $and$ \ CaCl _2$ reacts with it.
$CaO + H _2O + NH _3 \rightarrow NH _3 + Ca(OH) _2$
$CaCl _2 + 8NH _3 \rightarrow CaCl _2.8NH _3$
$P _2O _5 + 3H _2O + 6NH _3 \rightarrow 2(NH _4) _3PO _4$
$H _2SO _4 + NH _3 \rightarrow (NH _4) _2SO _4$
$NH _3$ gives White fumes of $NH _4Cl$ with $HCl$.
Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia
Nitrogen reacts with a metal $M$ to produce a compound $X$. This compound $X$ when dissolved in water forms pungent gas $Y$ which can be identified easily by the formation of white fumes in the presence of $HCl$.

Identify Y:

  1. Nitrogen dioxide

  2. Ammonia

  3. Nitrous oxide

  4. Nitric oxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$ 3Ca+{ N } _{ 2 }\xrightarrow [ \Delta  ]{  } { Ca } _{ 3 }{ N } _{ 2 } $

$ { Ca } _{ 3 }{ N } _{ 2 }+6{ H } _{ 2 }O\xrightarrow [  ]{  } 3Ca{ (OH) } _{ 2 }+2N{ H } _{ 3 } $
From the reaction we can see that the metal $ M $ is $Ca$ and pungent gas $ Y $ is Ammonia. 
Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

Cyanamide process is used in formation of-

  1. $N _2$
  2. $HNO _3$
  3. $NH _3$
  4. $PH _3$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cyanamide process is a nitrogen fixation process in which Calcium Carbide and nitrogen react with each other at a high temperature to form Calcium Cyanamide.
The following reaction takes place:

$CaC _2$ $+$ $N _2$ $ \longrightarrow $ $CaCN _2$ $+$ $C$
At high temperature Calcium Cyanamide react with steam as follows:
$CaCN _2$ $+$ $3H _2O$ $\longrightarrow $ $CaCO _3$ $+$ $2NH _3$
Hence, $NH _3$ is formed.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

In the Haber process for the industrial manufacturing of ammonia involving the reaction
${ N } _{ 2 }(g)+3{ H } _{ 2 }(g)\rightleftharpoons 2{ NH } _{ 3 }(g)$ at $200atm$ pressure in the presence of a catalyst, a temperature of about ${ 500 }^{ o }C$ is used. This is considered as optimum temperature for the process because:

  1. yield is maximum at this temperature

  2. catalyst is active only at this temperature

  3. energy needed for the reaction is easily obtained at this temperature

  4. rate of the catalytic reaction is fast enough while the yield is also appreciable for this exothermic reaction at this temperature
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In order to yield the maximum yield of ammonia, the temperature is lowered though $500^oC$ is not a low temperature. This temperature $(500^oC)$ is a compromise temperature to produce reasonably a high proportion of ammonia in the equilibrium mixture in a very short time.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

Which of the following catalyst is used in the Haber process for the manufacture of ammonia?

  1. Platinized asbestos

  2. Iron with a suitable promoter

  3. Copper oxide

  4. Alumina
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Haber process, also called the Haber Bosch process, is the industrial implementation of the reaction of nitrogen gas and hydrogen gas. It is the main industrial procedure to produce ammonia and catalyst used is iron with a suitable  promoter like $K _2O$, $CaO$, $SiO _2$, and $Al _2O _3$.
Option B is correct.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

Ammonia gas is not prepared by :

  1. reduction of sodium nitrite or sodium nitrate by the reaction of zinc dust and sodium hydroxide

  2. hydrolysis of calcium cyanamide

  3. heating ammonium chloride with slaked lime
  4. heating of $(NH _4) _2Cr _2O _7$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

(A) $NO _2^-+7[H]^-\xrightarrow {Zn/NaOH} NH _3+2H _2O; NO _3^-+9[H]^-\xrightarrow {Zn/NaOH} NH _3+3H _2O$
(B) $CaCN _2+3H _2O\rightarrow CaCO _3+2NH _3$
(C) $NH _4Cl+Ca(OH) _2\rightarrow 2NH _3+CaCl _2+2H _2O$
(D) $(NH _4) _2Cr _2O _7\rightarrow N _2+Cr _2O _3+4H _2O$

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

A solution of colorless salt H on boiling with excess NaOH produces a non-flammable gas. The gas evolution ceases after sometime upon addition of Zn dust to the same solution, the gas evolution restarts. The colourless salt(s) H is(are) :

  1. $NH _4NO _3$
  2. $NH _4NO _2$
  3. $NH _4Cl$
  4. $(NH _4) _2SO _4$
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation
Option (A), (B) are correct.
The colorless salt H is either $NH _4NO _3$ or $NH _4NO _2$. The colorless salt produces $NH _3$ gas (non-inflammable) on boiling with excess of $NaOH$. On addition of zinc dust (a reducing agent) to this solution, sodium nitrite or sodium nitrate will liberate $NH _3$ gas again.
 
$NH _4NO _3+ NaOH \longrightarrow NH _3+NaNO _3+H _2O$
$7NaOH+NaNO _3+4Zn\longrightarrow 4Na _2ZnO _2+NH _3+2H _2O$

$NH _4NO _2+NaOH \longrightarrow NaNO _2+NH _3+H _2O$
$3Zn+5NaOH+NaNO _2 \longrightarrow 3Na _2ZnO _2+NH _3$
Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

In Haber process 30 litres of dihydrogen and 30 litres of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture under the aforesaid condition in the end?

  1. 20 litres ammonia. 20 litres nitrogen, 20 litres hydrogen

  2. 10 litres ammonia, 25 litres nitrogen, 15 litres hydrogen

  3. 20 litres ammonia, 10 litres nitrogen, 30 litres hydrogen

  4. 20 litres ammonia, 25 litres nitrogen, 15 litres hydrogen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The reaction is N2 + 3H2 -> 2NH3. With 30L of each, H2 is the limiting reagent. Theoretical yield is 20L of NH3. At 50% yield, 10L of NH3 is produced. This consumes 5L of N2 and 15L of H2. Remaining: 25L N2, 15L H2, 10L NH3.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

In Haber process $30L$ of Dihydrogen and $30L$ of dinitrogen were taken for reaction which yielded only $50\% $of the expected product . what will be the composition of gaseous mixture under the aforesaid condition in the end?  

  1. $20L$ ammonia $10L$ nitrogen , $30L$ hydrogen
  2. $20L$ ammonia , $125L$ nitrogen , $25L$ ydrogen
  3. $20L$ ammonia , $20L$ nitrogen , $20L$hydrogen
  4. $10L$ ammonia , $25L$nitrogen , $15L$ hydrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The reaction is N2 + 3H2 -> 2NH3. With 30L of each, H2 is the limiting reagent. Theoretical yield is 20L of NH3. At 50% yield, 10L of NH3 is produced. This consumes 5L of N2 and 15L of H2. Remaining: 25L N2, 15L H2, 10L NH3.