Tag: oxoacids of halogens

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Questions Related to oxoacids of halogens

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

On heating $KClO _3$, we get :

  1. $KClO _2+O _2$
  2. $KCl+O _2$
  3. $KCl+O _3$
  4. $KCl+O _2+O _3$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
On heating $KClO _3$, we get $KCl+O _2$.

The reaction is as follows:
$2KClO _3 \longrightarrow 2KCl+ 3O _2$

When potassium chlorate is heated in the presence of manganese dioxide catalyst, it decomposes to form potassium chloride and oxygen gas. 
Multiple choice oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

Which products are expected from the disproportionation of hypochlorous acid?

  1. $HClO _3$ and $Cl _2O$
  2. $HClO _2$ and $HClO _4$
  3. $HCl $and $Cl _2O$
  4. $HCl $ and $HClO _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
$\displaystyle 3HClO \rightleftharpoons 2HCl + HClO _3$

It is a disproportionation reaction of hypochlorous acid where the oxidation number of chlorine from $+1$ to $-1$

Higher is Oxidation no. more is effective nuclear charge, lesser is size.

The disproportionation of hypochlorous acid gives $\displaystyle HCl $ and $\displaystyle HClO _3 $.

Hence option D is correct.

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

The following acids have been arranged in the order of decreasing acid strength. Identify the correct order: ClOH (I), BrOH (II), IOH (III).

  1. $I> II > III$
  2. $II>I>III$
  3. $III>II>I$
  4. $I>III>II$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For the same oxidation state, when the electronegativity of the halogen increases, the strength of the oxyacid increases.
$HOCI > HOBr > HOI$

Hence option A is correct.

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

Which one of the following oxy acid of fluorine exists ?

  1. $HOF$
  2. $HFO _{3}$
  3. $HFO _{4}$
  4. $HFO _{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In fluorine d-orbitals are absent so it shows only +1 oxidation state in oxo-acid,
but not + 3, + 5 or + 7. 


That's why unlike other members (halogens) fluorine only forms one oxoacid HOF.

Hence, option A is correct.

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

Among the oxyacids of chlorine, the strongest oxidising agent is:

  1. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{4}$
  2. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{3}$
  3. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{2}$
  4. $\mathrm{HCl}\mathrm{O}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$H\overset{+7}{Cl}O _4$ is strongest oxidising agent.
as Cl is in its highest oxidation state, i.e., +7.
Oxidation state $\alpha$ Oxdising nature 

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

Which one of the following oxyacids of chlorine is the least oxidizing in nature?

  1. $\mathrm{HOCl}$
  2. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{2}$
  3. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{4}$
  4. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{3}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\overset{+7}{HClO _{4}}$ a is in highest oxidation state so its oxidizing nature is least.

oxidation state $\alpha$ $\frac{1}{oxidising \ nature}$


Option C is correct.

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

Which of the following statements is not correct?

  1. All halogens except flourine from OXO-acids

  2. Hypohalous acids HOCI,HOBr and HOI are all strong acids

  3. Hypochlorous acid is the most stable among hypohalous acids

  4. Chlorous acid is the only halous acid known
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

There are also other halous acids like:
$HOBr _2$ which is Hydrobromous acid.
So D is wrong

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

Which of the following forms are the most basic in 0.1 M solution?

  1. $\mathrm{NaCl}$
  2. $\mathrm{NaOCl}$
  3. $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}\mathrm{O} _{2}$
  4. $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}\mathrm{O} _{3}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$NaCl^{-1}$
$NaOCl^{+1}$ - most basic as Cl is in +1 oxidation state and on hydrolysis it gives weak acid HOCl. Thus it is most basic among the given compounds.
$\overset{+3}{NaClO _{2}}$
$\overset{+5}{NaClO _{3}}$