Tag: ammonia

Questions Related to ammonia

Which statement is false:

  1. $\mathrm{N}\mathrm{H} _3$ is a Lewis base

  2. $\mathrm{N}\mathrm{H} _{3}$ molecule is triangular planar

  3. $\mathrm{N}\mathrm{H} _{3}$ does not act as reducing agent

  4. $\mathrm{N}\mathrm{H} _{3}$ (liquid) is used as a solvent


Correct Option: C

Ammoniacal liquor is :

  1. ammonia absorbed in water

  2. ammonium hydroxide

  3. aqueous solution of ammonia

  4. all of the above


Correct Option: D
Explanation:

Ammonical liquor is a solution of ammonia in water and is also called as ammonium hydroxide.

Which of the following has maximum complex forming ability with a given metal ion?

  1. $ \mathrm{P}\mathrm{H} _{3}$

  2. $ \mathrm{B}\mathrm{i}\mathrm{H} _{3}$

  3. $ \mathrm{N}\mathrm{H} _{3}$

  4. $ \mathrm{S}\mathrm{b}\mathrm{H} _{3}$


Correct Option: C
Explanation:

Due to higher tendency of nitrogen to donate its lone pair of electron to form coordinate bond which is not common in other hydrides of VA group elements, it has maximum complex forming ability.

The uses of ammonia is/are :

  1. manufacture of Explosives

  2. manufacture of Plastics and Raisins

  3. it is a main source of hydrogen

  4. all of the above


Correct Option: D
Explanation:

Uses of ammonia: as a refrigerant, In manufacture of  nitrogeneous fertilizer, Explosives, dry cells, nitrogen gas

Ammonia acts as a :

  1. reducing agent

  2. oxidising agent

  3. bleaching agent

  4. both A and C


Correct Option: A
Explanation:

Ammonia is a strong reducing agent. It dissolves alkali metals and other electropositive metals such as Mg,Ca,Sr,Ba etc. At low concentration deep blue solutions are formed these contain metal cations and solvated electrons.
${ Li }^{ + }+{ e }^{ - }\rightleftharpoons Li\ { Na }^{ + }+{ e }^{ - }\rightleftharpoons Na$

The oxidation state of nitrogen in ammonia molecule is -3.

  1. True

  2. False


Correct Option: A
Explanation:
The oxidation state of nitrogen in ammonia ($NH _3$) molecule is -3.
Let x be the oxidation state of nitrogen in ammonia. The oxidation state of hydrogen is $ \displaystyle +1$ .
$ \displaystyle x + 3 (+1)=0$
$ \displaystyle x+3=0$
$ \displaystyle x=-3$

What is the action of the Nessler's reagent on ammonia?

  1.  brown ppt.

  2. blue ppt.

  3. black ppt.

  4. green ppt.


Correct Option: A
Explanation:
Nesseler's reagent is an alkaline solution of Potassium tetraiodomercurate(II) ($K _2[HgI _4]$). It is prepared by combining potassium iodide (KI) and mercuric chloride ($HgCl _2$)
It is made slightly alkaline by adding KOH or NaOH.
On being reacted with gaseous ammonia it produces brown fumes and on being passed through a solution of ammonia, it gives a dirty brown precipitate. The reaction involved is:
$2K _2[HgI _4]+3KOH+NH _3 \rightarrow [OHg _2.NH _2]I+7KI+2H _2O$
The product formed is brown in colour and is used in test for ammonium ion.
It is a qualitative test for ammonia.
 $[OHg _2.NH _2]I$ is called Iodide of Million's base and has structure as:
$H _2N−Hg−O−Hg−I$ which is an insoluble/ brown ppt.

What is the action of the sodium metal on ammonia?

  1. Ammonia gas is released

  2. Hydrogen gas is released

  3. Oxygen gas is released

  4. Nitrogen gas id released


Correct Option: B
Explanation:
Sodium in ammonia can react in two way:
 1. in the absence of iron (III) catalyst:
the sodium metal gets dissolved in liquid ammonia. The result is a blue solution due to solvated electrons. This is the basis of the Birch Reduction reaction in the presence of alcohol.
2. In the presence of a bit of iron (III) catalyst:
Ammonia gas reacts with sodium metal to form sodium amide ($NaNH _2$) and hydrogen gas. The chemical reaction is as:
$2NH _3+2Na \rightarrow 2NaNH _2+H _2$
in the presence of a bit of an iron(III) catalyst, otherwise its a blue solution only.

When Ammonical common salt solution is saturated with carbon dioxide we obtain ?

  1. $NH _4HCO _3$

  2. $(NH _4) _2CO _3$

  3. $NaHCO _3$

  4. $Na _2CO _3$


Correct Option: C
Explanation:

Ammonical solution of common salt.

$CO _2+NH _3+NaCl+H _2O\longrightarrow NaHCO _3+NH _4Cl$
$\therefore$ By treating $CO _2$ with ammonical $NaCl$ we get sodium bicarbonate $(NaHCO _3)$ and ammonium sulphate.
Answer is option C.

Chlorine reacts with excess of ammonia to form:

  1. ${ NH } _{ 4 }Cl$

  2. ${ N } _{ 2 }+HCl$

  3. ${ N } _{ 2 }+{ NH } _{ 4 }Cl$

  4. ${ N } _{ 2 }+{ HCl} _{ 3 }$


Correct Option: C
Explanation:

Pure chlorine gas may react vigorously with ammonia gas. An excessive mix of the two gases in the air can produce hazardous compounds such as the explosive nitrogen trichloride. In facilities that use chloramination, the pure chlorine and ammonia need to be stored in separate, sealed rooms or buildings.

When ammonia is excess,

$3 Cl _2 + 8 NH _3 \rightarrow 6 NH _4Cl + N _2 (g)$