Tag: nitrogen and sulfur

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Questions Related to nitrogen and sulfur

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

Geometry of ammonia molecule and the hybridisation of nitrogen involved in it are: 

  1. $sp^3$- hybridisation and tetrahedral geometry
  2. $sp^3$- hybridisation and distorted tetrahedral geometry
  3. $sp^2$- hybridisation and trianguklar geometry

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(i) Hybridisation $= \frac{1}{2}$ [no.of $e^-$ in valence shell of central atom + no. of monovalent atoms + charge on anion - charge on cation]
(ii) Shape or geometry of molecule depends on lone pair and bond pair of electrons present in it.
Hybridisation  of N in $NH _3$
$=\frac{1}{2}(5+3+0)$
$=4$
$\therefore sp^3$ hybridisation.
$\because$, its has 3 bond pair and 1 lone pair of electrons, so it has distorted tetrahedron shape. 

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - 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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ammonia acts as a reducing agent in many reactions, such as reducing metal oxides to metals. The statement that it does not act as a reducing agent is therefore false.

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

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}$
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

Ammonia acts as a :

  1. reducing agent

  2. oxidising agent

  3. bleaching agent

  4. both A and C
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
${ Li }^{ + }+{ e }^{ - }\rightleftharpoons Li\ { Na }^{ + }+{ e }^{ - }\rightleftharpoons Na$

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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$
Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

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

  1. brown ppt.

  2. blue ppt.

  3. black ppt.

  4. green ppt.
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.