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Questions Related to chemistry

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 $H _3PO _3$.

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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

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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\$