Tag: p-block elements

Quizzes (27) Questions (202)

Questions Related to p-block elements

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

The correct order of basic character of oxo anions of chlorine is:

  1. $ Cl{O} _{ 4 }^{ - }>Cl{O} _{ 3 }^{ - }>Cl{O} _{ 2 }^{ - }>ClO^{ - }$
  2. $ ClO^- > Cl{O} _2^- > Cl{O} _3^- > Cl{O} _4^- $
  3. $ Cl{O} _3^- > Cl{O} _4^- > Cl{O} _2 > Cl{O}^- $
  4. $ Cl{O}^- > Cl{O} _2^- > Cl{O} _4^- > Cl{O} _3^- $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The basicity of oxoanions is inversely related to the stability of the conjugate acid. ClO- is the conjugate base of the weakest acid (HClO), making it the strongest base in the series. As the oxidation state of chlorine increases (from ClO- to ClO4-), the conjugate acid becomes stronger, making the anion a weaker base.

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

The correct statement (s) regarding, $\left( i \right)\,\,HCIO\,\,\,\,\left( {ii} \right)\,\,\,HCI{O _2}\,\,\,\,\left( {iii} \right)\,\,\,HCI{O _3}$ and $\left( {iv} \right)\,\,\,HCI{O _4}$, is 

  1. The number of $CI=O$ bond in $(ii)$ and $(iii)$ together is two.
  2. The numbers of lone pairs of electrons on $CI$ in $(ii)$ and $(iii)$ together is three.
  3. The hybridization of $CI$ in $(iv)$ is $s{p^3}$.
  4. Amongst $(i)$ to $(iv)$, the strongest acid is $(i)$.
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

Select the incorrect statement(s):

  1. ${NF _3}$ has a highest dipole moment among $CO$, ${NH _3}$ and ${NF _3}$
  2. $HF$ has a highest boiling point among ${CH _4}$, ${NH _3}$ and $HF$
  3. ${Cl _2}$ has a lowest boiling point among ${Cl _2}$, ${Br _2}$ and ${I _2}$
  4. ${HClO _3}$ is weakest acid among ${HIO _3}$, ${HBrO _3}$ and ${HClO _3}$
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

HF has a highest boiling point due to strong H bonding.
$Cl _2$ has a lowest boiling point due to lowest molar mass.
$CO$ has highest dipole moment due to linear structure.

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

Mixture of $KBr$ and $KBrO _3$ in acidic medium can be used as brominating agent.

The chemical reaction is, $ 5Br^{-} + xBrO^{-} _3 + 6H^{+} \rightarrow 3Br _y + 3H _2O$

Then $ x+y$ is :

  1. 6

  2. 3

  3. 5

  4. 11
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reaction of process:

$ 5Br^{-} + BrO _3^{-} + 6H^{+} \rightarrow 3Br _2 + 3H _2O$
      -1               +5                               0

$x$ = 1 ,$y$ = 2

$x +y$ = 3

Here, bromide ion oxidises and $BrO _3^-$ reduces and bromine forms as a product.

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

Which of the following is the weakest  base as per the Bronsted concept ?

  1. $ [ClO _4]^- $
  2. $ [ClO _3]^-$
  3. $ [ClO _2]^-$
  4. $ [ClO]^-$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The Bronsted-Lowry definition of an acid is a proton donator and a base is a proton acceptor. 

According to Bronsted concept, conjugate base of strongest acid is weakest.

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

so weakest base is $ClO _4^-$.
Multiple choice oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

Which has peroxy linkage ?

  1. Perchloric acid

  2. Hypochlorous acid

  3. Para perchloric acid

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Perchloric acid is a mineral acid with the formula HClO₄. Usually found as an aqueous solution, this colorless compound is a stronger acid than sulfuric acid and nitric acid

Hypochlorous acid  $HOCl$ is a weak acid that forms when chlorine dissolves in water, and itself partially dissociates, forming hypochlorite,

| Oxidation state of the halogen inthe acid |                                Oxoacids |  Structure | | --- | --- | --- | | $Cl$ |  $Br$ |  $I$ | |  $+1$ | $HClO$  |  $HBrO$ |  $HlO$ |  $H-O-X$ | |  $+3$ | $HClO _2$ |   |   |  $H-O-x\to O$ | |  $+5$ | $HClO _3$  | $HBrO _3$  | $HlO _3$  |  $H - O - \overset{O}{\overset{\uparrow}{X}} \to O$ | |  $+7$ |  $HClO _4$ |  $HBrO _4$ | $HlO _4$  |  $HO - \underset{O}{\underset{\downarrow}{\overset{O}{\overset{\uparrow}{X}}}} \to O$ |
Multiple choice oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

Select correct statements (s):

  1. $ClO _2\ and \ Cl _2O$ are used as bleaching agents for paper pulp and textiles.
  2. $OCl^-$ salts are used as detergents.
  3. $OCl^-$ disproportionates in alkaline medium.
  4. $BrO^- _3$ is oxidised to $Br^-$ in acidic medium.
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

A. The oxides of chlorine such as $ClO _2$  and $Cl _2O$ are used as bleaching agents for paper pulp and textiles. Thus, the option A is correct.

B. $OCl^-$ salts cannot be used as detergents. Thus, the option B is incorrect.

C. In alkaline medium, $OCl^-$ disproportionates. $3ClO^- \xrightarrow {\Delta} 2Cl^-+ClO _3^-$. Thus, the option C is correct.

D. In acidic medium, $BrO _3^-$ is reduced to $Br^-$. $KBrO _3 + 3H _2SO _3 \rightarrow KBr + 3H _2SO _4$ Thus, the option D is incorrect.