Tag: oxoacids of halogens

Questions Related to oxoacids of halogens

The increasing order of the acidity of the following acids is:


 l) $H _{2}SO _{3}$
ll) $H _{3}PO _{3}$ 
lll) HClO$ _{3}$

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. l>lll>ll

  2. l > ll > lll

  3. lll>l >lI

  4. ll>lll>l

Show answer
Correct Option: C
Explanation:
Here as the non-metallic nature of the central atom increases, its acidity increases in its oxyacids Thus, increasing order of acidity will be:
III > I >II

Match the following


Set-l (Cl-O bond length)       Set -ll($\mathrm{A}^{0})$
$\mathrm{A}) H\mathrm{C}lO$                                 1)$ 1.64$
$\mathrm{B}) HClO _{2}$                               2$) 1.70$
$\mathrm{C}) HClO _{3}$                               3$)$ 1.45
$\mathrm{D}) HClO _{4}$                               4$) 1.57$

The correct matching is:

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. A-1, B-2, C-3, D-4

  2. A-2, B-3, C-4, D-1

  3. A-2, B-1, C-4, D-3

  4. A-2, B-1, C-3, D-4

Show answer
Correct Option: C
Explanation:

Bond order $\propto \ \frac{1}{Bond\ length}$


Bond order of $HClO _4 > HClO _3 > HClO _2> HClO$

Bond length
$HClO > HClO _2 > HClO _3 > HClO _4$

Number of valence electrons present in atoms of $HClO _{4},HClO _{3},HClO _{2}$ respectively are :

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $32,26,20$

  2. $26,20,14$

  3. $36,30,24$

  4. $28,22,16$

Show answer
Correct Option: A
Explanation:

Number of valence electrons present in atoms of $HClO _{4},HClO _{3},HClO _{2}$ are32,26,20 respectively.
Number of valence electrons present in atoms of  $HClO _{4}$ are $1+7+4(6)=32$
Number of valence electrons present in atoms of  $HClO _{3}$ are $1+7+3(6)=26$
Number of valence electrons present in atoms of  $HClO _{2}$ are $1+7+2(6)=20$

Which of the following molecule have highest thermal stability ?

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $HClO$

  2. $HClO _2$

  3. $HClO _3$

  4. $HClO _4$

  5. All of the above have equal thermal stability

Show answer
Correct Option: D
Explanation:

As the number of oxygen atoms in hypochlorous acid increases the thermal stability increases so $HClO _4$ is the most stable thermally.

Which of the following is called Berthelot's salt? 

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $(NaPO _3) _6$

  2. $NaOCl$

  3. $KClO _3$

  4. $KHF _2$

Show answer
Correct Option: C
Explanation:
Potassium chlorate ($KClO _3$) is called Berthelot salt, which on thermal decomposition gives potassium chloride and oxygen gas.
Hence option $C$ is correct.

Which selection is the correct formula for the chlorate ion?

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. ${Cl}^{-}$

  2. $Cl{O}^{-}$

  3. $Cl{O} _{2}^{-}$

  4. $Cl{O} _{3}^{-}$

  5. $Cl{O} _{4}^{-}$

Show answer
Correct Option: D
Explanation:

The correct formula for the chlorate ion is $Cl{O} _{3}^{-}$
The formula $Cl{O}^{-}$ represents hypochlorite ion.
The formula $Cl{O} _{2}^{-}$ represents chlorite ion.
The formula $Cl{O} _{4}^{-}$ represents perchlorate ion.

Which of the following is stable in solid state?

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $HClO _3$

  2. $HBrO _3$

  3. $HIO _3$

  4. All of these

Show answer
Correct Option: C
Explanation:

$HIO _3$  most stable among the given acids because it do not ionize itself easily.

Hence option $C$ is correct.

$NaOCl$ is used as a bleaching agent and sterilising agent. It can be prepared by the action of:

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $NaCl$ with $H _2O$

  2. $NH _4Cl$ with $NaOH$

  3. $Cl _2$ with cold and dil. $NaOH$

  4. $Cl _2$ with hot and conc. $NaOH$

Show answer
Correct Option: C
Explanation:
Chlorine with cold and dilute sodium hydroxide give mixture of chloride salt, hypochlorite and water.

$Cl _2 (l) + 2NaOH (aq) \rightarrow NaCl+ NaClO (aq) + H _2O(l) $

Chlorine with hot and dilute sodium hydroxide give mixture of chloride salt, hypochlorite and water.

$3 Cl _2 (l) + 6 NaOH (aq) \rightarrow 5 NaCl + NaClO _3 (aq) + 3 H _2O (l) $

Hence, the correct option is $C$

Which of the following does exist?

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $HFO _2$

  2. $HClO _2$

  3. $HBrO _2$

  4. $HIO _2$

Show answer
Correct Option: B
Explanation:
$HClO _2$ is a chlorous acid which is oxyacid of halogen.
Remaining oxyacids of halogens do not exist.

Bromous acid $HBrO _2$ and Iodous acid $HIO _2$  and fluorous acid are not likely to exist in nature as they would decompose into oxides and water vapour when trying to isolate them from their respective acid solutions.

Hence, option $B$ is correct.

${ COCl } _{ 2 }$ gas dissociates according to the equation
${ COCl } _{ 2 }(g)\ \rightleftharpoons \ CO(g)\ +\ { Cl } _{ 2 }(g)$
When ${ COCl } _{ 2 }$ is heated to 700 K at 100 kPa, density of the gas mixture at equilibrium is $1.2\ { gdm }^{ -3 }$. The percentage degree of dissociation of ${ COCl } _{ 2 }$ is: 

$(R = 8.314\ kPa\ { dm }^{ 3 } { K }^{ -1 }\ { mol }^{ -1 })$

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. 41

  2. 81

  3. 60

  4. 20

Show answer
Correct Option: A