Tag: p- block elements-ii

Questions Related to p- block elements-ii

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}$

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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 $[PBr _{4}]^{+}Br^{-}$

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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

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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

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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).