Tag: p- block elements-ii

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Questions Related to p- block elements-ii

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

Which selection is the correct formula for the chlorate ion?

  1. ${Cl}^{-}$
  2. $Cl{O}^{-}$
  3. $Cl{O} _{2}^{-}$
  4. $Cl{O} _{3}^{-}$
  5. $Cl{O} _{4}^{-}$
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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

  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. $NaOH$
Reveal answer Fill a bubble to check yourself
C Correct answer
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 $C$
Multiple choice oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

Which of the following does exist?

  1. $HFO _2$
  2. $HClO _2$
  3. $HBrO _2$
  4. $HIO _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

${ COCl } _{ 2 }$ 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: 

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

  1. 41

  2. 81

  3. 60

  4. 20
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using the ideal gas law PV=nRT and the relationship between density, molar mass, and degree of dissociation (alpha), one can solve for alpha. Given the density 1.2 g/dm3 at 700K and 100 kPa, the calculation yields approximately 41%.

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

Bleaching action of $CaOCl _2$ is due to :

  1. Nascent oxygen
  2. $Ca$
  3. $Cl$
  4. $HCl$
Reveal answer Fill a bubble to check yourself
A,C Correct answer
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.

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

Match the correct use for the following chemicals:

$ KClO 3 $ is used ______.

$ KClO _4 $ is used as ________.

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

  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
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
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.

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

Choose the correct statements:

  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 $Cl _2O _3$.
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
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.