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Questions Related to chemistry

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
 $\displaystyle C _{12}H _{22}O _{11}+36HNO _3 \rightarrow 6(COOH) _2+36NO _2+23H _2O$