Tag: p-block elements

Questions Related to p-block elements

Which one of the following oxy acid of fluorine exists ?

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

  1. $HOF$

  2. $HFO _{3}$

  3. $HFO _{4}$

  4. $HFO _{2}$

Show answer
Correct Option: A
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.

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

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

  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. $\mathrm{HCl}\mathrm{O}$

Show answer
Correct Option: A
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 

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

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

  1. $\mathrm{HOCl}$

  2. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{2}$

  3. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{4}$

  4. $\mathrm{H}\mathrm{Cl}\mathrm{O} _{3}$

Show answer
Correct Option: C
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.

Which of the following statements is not correct?

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

  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

Show answer
Correct Option: D
Explanation:

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

The anhydride of $\mathrm{H}\mathrm{Cl}\mathrm{O} _{4}$ is:

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

  1. $\mathrm{Cl}\mathrm{O} _{4}$

  2. $\mathrm{Cl} _{2}\mathrm{O} _{7}$

  3. $\mathrm{Cl}\mathrm{O} _{2}$

  4. $\mathrm{Cl}\mathrm{O} _{3}$

Show answer
Correct Option: B
Explanation:

$2HClO _4\ \overset{-H _2O}{\rightarrow}Cl _2O _7$
$\therefore $  Anhydride of $2HClO _4$ is $Cl _2O _7$

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

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

  1. $\mathrm{NaCl}$

  2. $\mathrm{NaOCl}$

  3. $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}\mathrm{O} _{2}$

  4. $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}\mathrm{O} _{3}$

Show answer
Correct Option: B
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.
$\overset{+3}{NaClO _{2}}$
$\overset{+5}{NaClO _{3}}$

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.