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Compounds of phosphorus- pcl5 - class-XII

Description: compounds of phosphorus- pcl5
Number of Questions: 25
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Tags: p- block elements-ii p-block elements chemistry the p-block elements
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Which of the following is not correctly matched?

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $PCl _{5}$ - $sp^{3}d$ hybridisation.

  2. $PCl _{3}$ - $sp^3$ hybridisation.

  3. $PCl _{5}$ (solid) - $[PtCl _{4}]^{+}$+ $[PtCl _{6}]^{-}$.

  4. $PCl _{5}$ - brownish powder.

Show answer
Correct Option: D
Explanation:


 Colour of $PCl _5$ is not brownish but a greenish yellow crystalline solid with an irritating odour.

Hence option D is correct.

On reaction with $Cl _{2}$, phosphorus forms two types of halides 'A' and 'B'. Halide 'A' is yellowish-white powder but halide 'B' is colourless oily liquid. What would be the hydrolysis products of 'A' and 'B' respectively?

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $H _{3}PO _{4}$,$H _{3}PO _{3}$

  2. $HOPO _{3}$, $H _{2}PO _{2}$

  3. $H _{3}PO _{3}$,$H _{3}PO _{4}$

  4. $HPO _{3}$,$H _{3}PO _{3}$

Show answer
Correct Option: A
Explanation:

$P+Cl _2\longrightarrow \underset {(B)}{PCl _3} +\underset {(A)}{PCl _5}$

$PCl _5+4H _2O\longrightarrow H _3PO _4+5HCl$
$PCl _3+3H _2O\longrightarrow H _3PO _3+3HCl$

In solid state $PCl _{5}$ is a :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. covalent solid

  2. octahedral structure

  3. ionic solid with $[PCl _{6}]^{+}$ octahedral and $[PCl _{4}]^{-}$ tetrahedral

  4. ionic solid with $[PCl _{4}]^{+}$ tetrahedral and $[PCl _{6}]^{-}$ octahedral

Show answer
Correct Option: D
Explanation:

In solid state $PCl _5$ tries  to exist as oppositely charged ions like

(1) $PCl _4^{+}$ and (2) $PCl _6^{-}$ as the ionic bonding enhances the crystalline nature .

also $PCl _4^{+}$  is tetrahedral , while $PCl _6^{-}$ is octahedral . these structure fit well into each other which gives more stability to solid structure .

Hence option D is correct.

Among the following, the number of compounds that can react with $PCl _{5}$ to give $POCl _{3}$ is: 


$O _{2},\ CO _{2},\ SO _{2},\ H _{2}O,\ H _{2}SO _{4},\ P _{4}O _{10}$

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. 4

  2. 5

  3. 3

  4. 6

Show answer
Correct Option: A
Explanation:

$PCl$ on reaction with these $4$ compounds produces $POCl _3$:


$PCl _5+SO _2\rightarrow POCl _3+SOCl _2$
$PCl _5+H _2O\rightarrow POCl _3+2HCl$
$PCl _5+H _2SO _4\rightarrow SO _2Cl _2+2POCl _3+2HCl$
$6PCl _5+P _4O _{10}\rightarrow 10POCl _3$.

The most powerful chlorinating agent is :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

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

  2. $\mathrm{Cl} _{2}\mathrm{O}$

  3. $\mathrm{P}\mathrm{Cl} _{5}$

  4. $\mathrm{Cl}\mathrm{O} _{2}$

Show answer
Correct Option: C
Explanation:

$PCl _{5}$ readily dissociates into $PCl _{3}$ and chlorine gas and therefore acts as a good chlorinating agent.

Which of the following pentahalides does not exist?

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $\mathrm{P}\mathrm{F} _{5}$

  2. $\mathrm{P}\mathrm{Cl} _{5}$

  3. $\mathrm{P}\mathrm{B}\mathrm{r} _{5}$

  4. $\mathrm{PI} _{5}$

Show answer
Correct Option: D
Explanation:

SI is too big for small P.
SI atoms cannot fil around small P. So $PI _{s}$ does not exist.

With hot water P$ _{2}$O$ _{5}$ gives :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. H$ _{3}$PO$ _{3}$

  2. H$ _{3}$PO$ _{4}$

  3. H$ _{3}$PO$ _{2}$

  4. HPO$ _{3}$

Show answer
Correct Option: B

Which acid is not formed by the action of water on phosphorus pentaoxide ?

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $ H P O _3 $

  2. $ H _4 P _2 O _7 $

  3. $ H _3 PO _4 $

  4. $ H _3 PO _3 $

Show answer
Correct Option: C

The hybrid states of phosphorous atoms in $PCl _{5}$ and $PBr _{3}$ in gaseous phase are $sp^{3}d$. But in solid $PCl _{5}$, phosphorous shows $sp^{3}d^2$ hybrid state. While $P$ in $PBr$ is in $sp^{3}$ hybrid state. This is because :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $PCl _{5}$ in solid form exists as $[PCl _{4}]^{+}[PCl _{6}]^{-}$

  2. $PBr _{5}$ in solid form exists as $[PCl _{4}]^{+}[PBr _{6}]^{-}$

  3. $PCl _{5}$ in solid form exists as $[PCl _{4}]^{+}Cl^{-}$

  4. $PBr _{5}$ in solid form exists as $[PBr _{4}]^{+}Br^{-}$

Show answer
Correct Option: A,D
Explanation:
Both $PCl _{5}$ and $PBr _{5}$ have triagonal bipyramidal geometry this is not  a regular structure and is not very stable.

Therefore $PCl _{5}$ splits up into two more stable octahedral and tetrahedral  structures .

$PCl _{5}$ in solid form exists as $[PCl _{4}]^{+}[PCl _{6}]^{-}$. The hybridisation state of $P$ in $[PCl _{4}]^{+}$ and $[PCl _{6}]^{-}$ is 
$sp^3$ and $sp^3d^2$ respectively.

$PBr _{5}$ in solid form exists as $[PBr _{4}]^{+}Br^{-}$ and hybridisation state of $P$ in $[PBr _{4}]^{+}$ is $sp^3$ hybridised.

The metallic character of the element of IV A group _______________.

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. Decreases from top to bottom

  2. Has no significance

  3. Does not change

  4. Increase from top to bottom

Show answer
Correct Option: D
Explanation:

Metallic character increases as you move down an element group in the periodic table.

Identify the correct statements.

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. Calcium cyanamide on treatment with steam under pressure gives ${NH _3}$ and ${Ca CO _3}$

  2. ${PCl _5}$ is kept in well stopped bottle because it reacts readily with moisture

  3. Ammonium nitrite on heating gives ammonia and nitrous acid

  4. Cane sugar reacts with conc. ${H NO _3}$ to form oxalic acid

Show answer
Correct Option: A,B,D
Explanation:

(A) Calcium cyanamide on treatment with steam under pressure gives ${NH _3}$ and ${Ca CO _3}$
 $\displaystyle CaCN _2+3H _2O \text { (steam)} \xrightarrow {\displaystyle \text {3 atm}} CaCO _3+ 2NH _3$
(B) ${PCl _5}$ is kept in well stopped bottle because it reacts readily with moisture
 $\displaystyle PCl _5+H _2O \rightarrow POCl _3+2HCl$
 $\displaystyle PCl _5+4H _2O \rightarrow H _3PO _4+5HCl$
(C) Ammonium nitrite on heating gives nitrogen and water.
 $\displaystyle NH _4NO _2 \rightarrow N _2  +2H _2O$
(D)Cane sugar reacts with conc. ${H NO _3}$ to form oxalic acid
 $\displaystyle C _{12}H _{22}O _{11}+36HNO _3 \rightarrow 6(COOH) _2+36NO _2+23H _2O$

Choose the correct options:

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. PCl$ _5$ (solid) dissociates into PCl$ _4^+$ and PCl$ _6^-$.

  2. LiH reacts with AlH$ _3$ forming LiAlH$ _4$.

  3. $NH _3$ is protonated.

  4. $H _3PO _2$ on heated forms $PH _3$ and $H _3PO _3$.

Show answer
Correct Option: A,B
Explanation:

PCl$ _5$ (solid) dissociates into PCl$ _4^+$ and PCl$ _6^-$. LiH reacts with AlH$ _3$ forming LiAlH$ _4$. These are facts. $NH _3$ is not protonated. On protonation, it forms $NH _4^+$ion. $H _3PO _2$ on heating does not form $PH _3$ and $H _3PO _3$.

In the given reaction $CI$  replaces one of the H-atoms in $CH _3CH _2OH$. This $H$ is of :


$PCI _5+C\underset{\overline{X}}{H _3}C\underset{\overline{Y}}{H _2}\underset{\overline{Z}}{OH} \longrightarrow$

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. C (in X)

  2. C (in Y)

  3. O (in Z)

  4. any of X, Y and Z

Show answer
Correct Option: C

The solid $PCl _5$ exists as :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $PCl _3$

  2. $PCl _4^+$

  3. $PCl _6^-$

  4. $PCl _4^+$ and $PCl _6^-$

Show answer
Correct Option: D
Explanation:

In solid state, $PCl _5$  prefers to exist as oppositely charged ions like $[PCl _4]^+$ & $[PCl _6]^-$ as the ionic bonding enhances the crystalline nature.

Also, $[PCl _4]^+$ is tetrahedral while $[PCl _6]^-$ is octahedral, these structures fit well into each other providing extra stability to the soild structure.

Solid crystalline $PCI _5$ has structure which of the following?

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. Bi-pyramidal 

  2. Octahedral and tetrahedral ions

  3. Square-pyramidal 

  4. Pentagonal 

Show answer
Correct Option: B
Explanation:

In solid state, $PCl _5$ prefers to exist as oppositely charged ions like $[PCl _4]^+$ & $[PCl _6]^-$ as the ionic bonding enhances the crystalline nature. Also, $[PCl _4]^+$ is tetrahedral while $[PCl _6]^-$ is octahedral, these structures fit well into each other providing extra stability to the soild structure.

In crystalline state $PCl _5$ exists as :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $[PCl _4]^+Cl^-$

  2. $[PCl _4]^+[PCl _6]^-$

  3. $[PCl _3]^{2+}+2Cl^-$

  4. $[PCl _6]^+[PCl _4]^-$

Show answer
Correct Option: B
Explanation:

In solid state, $PCl _5$ prefers to exist as oppositely charged ions like $[PCl _4]^+ [PCl _6]^-$ as ionic bonding enhances the crystalline nature. Also, $[PCl _4]^+$ is tetrahedral while $[PCl _6^-]$ is octahedral. These structures fit well into each other providing extra stability to the solid structure.


Hence, the correct option is (B).

What is the hybridization state of cation part of solid $PCl _5$?

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $sp^3d^2$

  2. $sp^2$

  3. $sp^3$

  4. $sp^3d$

Show answer
Correct Option: C
Explanation:

In solid state, $PCl _5$ prefers to exist as oppositely charged ions like $[PCl _4]^+ PCl _6^-$ as ionic bonding enhances the crystalline nature. Also, $[PCl _4]^+  = sp^3$ is tetrahedral while $[PCl _6^-]$ is octahedral. These structures fit well into each other providing extra stability to the soild structure.

Thus, solid $PCl _5$ exist as $[PCl _4]^+[PCl _6]^-$
The cationic part of $PCl _5$ is$[PCl _4]^+$.
In $PCl _4^+$, Phosphorous forms $4\ \sigma-bonds$. 
Hence, the hybridization is $sp^3$.

In presence of small amount of water, $PCl _5$ hydrolyzes to form :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $PCl _3$

  2. POCl

  3. $POCl _3$

  4. $H _3PO _3$

Show answer
Correct Option: C
Explanation:

In limited amount of water,
$PCl _5 (s)+H _2O (l)\rightarrow POCl _3(l) + 2HCl(aq)$
In large amount of water,
$PCl _5(s) +4H _2O(l)\rightarrow H _3PO _4+ 5HCl$

Hence, the correct option is (C).

Which of the following statements is/are correct?

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. Solid $PCl _5$ exists as tetrahedral $PCl^{+} _{4}$ and octahedral $PCl^{-} _{6}$ ions.

  2. Solid $PBr _5$ exists as $PBr^{+} _{4}Br^{-}$.

  3. Solid $N _2O _5$ exists as $NO^{-} _3$ and $NO^{+} _{2}$.

  4. Oxides of phosphorus $P _2O _3$ and $P _2O _5$ exist as monomers.

Show answer
Correct Option: A,B,C
Explanation:

Solid $PCl _5$ exists as tetrahedral $PCl^{+} _{4}$ and octahedral  $PCl^{-} _{6}$ ions.
$2PCl _5 \rightleftharpoons [PCl _4]^+ (tetrahedral) + [PCl _6]^-(octahedral)$
Solid $PBr _5$ exists as $PBr^{+} _{4}Br^{-}$.
$PBr _5 \rightleftharpoons [PBr _4]^+(tetrahedral) Br^-$
Solid $N _2O _5$ exists as $NO^{-} _3$ and $NO^{+} _{2}$.
$N _2O _5 \rightleftharpoons NO^{-} _3 + NO^{+} _{2}$
Oxides of phosphorus $P _2O _3$ and $P _2O _5$ exist as dimers $P _4O _6$ and $P _4O _{10}$. 

All these are facts. Thus, the options A, B and C are correct and option D is incorrect.

$PCl _5$ exists as solid in the form of $[PCl _4]^{+} [PCl _6]^{-}$, and it is a non conductor of electricity.

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. True 

  2. False

  3. Ambiguous

  4. None of the above

Show answer
Correct Option: A
Explanation:

In solid state, position of ions are fixed, and hence, cannot conduct electricity.

In the following reactions :
$(i) P{Cl} _{5}+{SO} _{2}\rightarrow A+B$
$(ii) A+MeCOOH\rightarrow C+{SO} _{2}+HCl$
$(iii) 2C+{Me} _{2}Cd\rightarrow 2D+CD{Cl} _{2}$ The compound (C) is:

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $Me-CH -Cl _2$

  2. $Me-CH _2 -Cl$

  3. $Me-\underset { \parallel \ O }{ C } -Cl$

  4. $Me-C -Cl _3$

Show answer
Correct Option: C
Explanation:

$(i) P{Cl} _{5}+{SO} _{2}\rightarrow SO{Cl} _{2} (A)+PO{cl} _{3} (B)$

(ii) $SO{Cl} _{2}+MeCOOH\rightarrow Me-\underset { \parallel \ O }{ C } -Cl (C)+{SO} _{2}+HCl\$

Action of $PCl _5$ on $SO _2$ chiefly yields :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $POCl _3$

  2. $P _4S _3$

  3. $SO _2Cl _2$

  4. $SO _3$

Show answer
Correct Option: A
Explanation:

$PCl _{5}+SO _{2}\rightarrow POCl _{3}+SOCl _{2}$

Unsymmetrical $PCl _5(s)$ splits into $PCl _4^+$ and  $PCl _6^-$.

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. True

  2. False

  3. Ambiguous

  4. None of these

Show answer
Correct Option: A
Explanation:

The cation $PCl^+ _4$ and the anion $PCl _6^-$ are tetrahedral and octahedral which are more stable then $PCl _5$ due to symmetry.

$PCl _5$ in soild state dissociates into $PCl^+ _4$ and $PCl^- _6$.

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

The given statement is True.
 
$\displaystyle PCl _5$ molecule has trigonal bipyramidal geometry which is unstable as axial P-Cl bonds are slightly larger than equatorial P-Cl bonds. Also some bond angles are of 90 deg and others are of 120 deg. Due to this, trigonal bipyramidal geometry is not regular and not stable. Hence, in solid state, $\displaystyle PCl _5$ molecule dissociates into tetrahedral $\displaystyle [PCl _4]^+$ and octahedral $\displaystyle [PCl _6]^-$
$\displaystyle 2PCl _5 \rightleftharpoons [PCl _4]^+ +[PCl _6]^- $

The compound molecular in nature in gas phase but ionic in solid state is :

chemistry p- block elements-ii compounds of phosphorus- pcl5 phosphorus halides compounds of phosphorus compounds of phosphorus - pcl3

  1. $ PCl _5 $

  2. $ CCl _4 $

  3. $ PCl _3 $

  4. $ POCl _3 $

  5. None of the above

Show answer
Correct Option: A
Explanation:

In gaseous and molten state $PCl _5$ is neutral molecule with trigonal bipyramidal symmetry.

In solid state $PCl _5$ is ionic which forms $PCl _4^{+}$, $PCl _6^{-}$. The cation and anion $PCl _4^{+}$, $PCl _6^{-}$ are tetrahedral and octahedral respectively.

Hence option A is correct.

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