Tag: p-block elements

Questions Related to p-block elements

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

On boiling an aqueous solution of $KClO _{3}$ with $I _{2}$ the products obtained are:

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

  1. $KIO _{3} + Cl _{2}$

  2. $KCl + I _{2}O _{5}$

  3. $KIO _{4} + Cl _{2}$

  4. none of the above

Show answer
Correct Option: D
Explanation:

$KClO _3 + 6HCl + I _2 \rightarrow 2ICl _3 + KI + 3H _2O$ 

Bleaching action of $CaOCl _2$ is due to :

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

  1. Nascent oxygen

  2. $Ca$

  3. $Cl$

  4. $HCl$

Show answer
Correct Option: A,C
Explanation:

Calcium oxychloride ($CaOCl _2$) is known as bleaching powder. When it is treated with excess of dilute acids, chlorine is evovled which is responsible for the bleaching action of bleaching powder. Due to the evolution of nacent oxygen, it acts an an oxidising and bleaching agent.

Match the correct use for the following chemicals:

$ KClO 3 $ is used ______.

$ KClO _4 $ is used as ________.

$ Mg(ClO _4) _2 $ is used as ________.

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

  1. $ KClO _3 $- Explosive

  2. $ KClO _4 $- Fireworks and flares

  3. $ Mg(ClO _4) _2 $- Dry batteries

  4. $ KClO _3 $- Fireworks and flares

  5. $ Mg(ClO _4 ) _2$- Explosive

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

$ KClO _3 $- Explosives.May explode under prolonged exposure to heat or fire.


$ KClO _4 $- Fireworks and flares. It is an oxidizer in the sense that it exothermically transfers oxygen to combustible materials, greatly increasing their rate of combustion relative to that in air.


$ Mg(ClO _4) _2 $- Dry batteries.It is drying agent for gases. It can remove water from gases (with no organic contaminants) at the rate of 0.001mgwater/l.

Choose the correct statements:

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

  1. The anyhdride of $HOCl$ is $Cl _2O$.

  2. The anyhdride of $HClO _2$ is $ClO _2$.

  3. The anyhdride of $HClO _3$ is $Cl _2O _6$.

  4. The anyhdride of $HClO _4$ is $Cl _2O _7$.

  5. The anyhdride of $HClO _3$ is $Cl _2O _3$.

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

The anyhdride of $HOCl$ is $Cl _2O$.
The anyhdride of $HClO _2$ is $ClO _2$.
The anyhdride of $HClO _3$ is $Cl _2O _6$.
The anyhdride of $HClO _4$ is $Cl _2O _7$.
Anhydrides on reaction with water will give you corresponding acid.