Tag: group 15 elements

Questions Related to group 15 elements

How many oxides of monomeric nature can nitrogen form?

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. $1$

  2. $2$

  3. $4$

  4. $5$

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Correct Option: A
Explanation:

$N$ has 5 valence electron, therefore molecules with $N _2O _x$ will have even number of electrons and will be non radical. For monomeric oxide, $N _2O$ is the only monomeric nitrogen oxide.

Therefore option A is correct.

Select the correct statement for brown ring test.

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. Nitrates are converted to $NO$

  2. $NO$ forms complex with $Fe$

  3. $Fe^{2+}$ acts as reducing agent here.

  4. Brown colour is due to the complex formation.

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Correct Option: A,B,C,D
Explanation:
$ 2HNO _3+ 3H _2SO _4 + 6FeSO _4 \rightarrow 3Fe _2(SO _4) _3 + 2NO + 4H _2O $ $[Fe(H _2O) _6]SO _4+NO \rightarrow [Fe(H _2O) _5(NO)]SO _4+H _2O$ Nitrates are converted into nitric oxide. $NO$ forms complex with $Fe$. $Fe^{2+}$ acts as reducing agent. $[Fe(H _2O) _5(NO)]SO _4$ is brown coloured complex formed.

Which of the following do have $p _{\pi}$ - $d _{\pi}$ bonding?

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. $NO^- _3$

  2. $SO^{-2} _3$

  3. $BO^{-3} _3$

  4. $CO^{-2} _3$

Show answer
Correct Option: B
Explanation:

$p\pi-d\pi$ bonding includes d-orbitals,if you observe the options only S belongs to $3^{rd}$ period and has d-orbitals(though unoccupied in ground state).

Other options $C$ and $N$ belongs to $2^{nd}$ period while B belongs to $1^{st}$ period and doesn't have d-orbitals.

Which of the following elements occur free in nature?

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. Nitrogen

  2. Phosphorus

  3. Arsenic

  4. Antimony

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Correct Option: A
Explanation:

The nitrogen which exists free in nature which is made up of 78% of Earth atmosphere and naturally found in mineral deposits, soil and organic compounds.

Single $N-N$ bond is weaker than the single $P-P$ bond. This is because of:

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. larger $N-N$ bond length in comparison to $P-P$ bond length

  2. high interelectronic repulsion of the non-bonding electrons, owing to the small $N-N$ bond length in comparison to that in $P-P$ single bond

  3. higher electronegativity of $N$ in comparison to $P$

  4. smaller atomic size of $N$ as compared to that of $P$

Show answer
Correct Option: B,D
Explanation:

$N-N$ single bond is weaker than $P-P$ bond due to smaller size of $N$ as compared to $P$. Smaller size of $N$ leads to smaller $N-N$ bond length. As a result, the lone pair of electrons on the both the $N$ atoms repel each other leading to unstability or weakening of $N-N$ bond. Because of larger size of $P$ atom, $P-P$ bond length is more and lone pair-lone pair repulsion between $P$ atoms is less which makes the $P-P$ bond stronger than $N-N$ bond.

Alkali metals dissolve in liquid ammonia and produces _______.

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. deep blue solution

  2. a solution which are conducting in nature

  3. red coloured solution

  4. Both $1$ and $2$

Show answer
Correct Option: D
Explanation:

Alkali metal when reacts with liquid ammonia reaction is given by,


$ M +(x+y) NH _3\rightarrow M^+(NH _3)x + e^{-}(NH _3) _y$

 this electrons is free and gives very good conductivity as well blue colour.

$N _{2}H _{4}+2H _{2}O _{4}\rightarrow 4H _{2}O _2$. 


This equation suggests the use of $H _{2}O _{2}$ as :

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. Bleaching agent

  2. Antisepics

  3. Restoring colour of old paintings

  4. Rocket Propellant

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Correct Option: D

$CN^-$ and $N _2$ are isoelectronic. But in contrast to $CN^-, N _2$ is chemically inert because of:

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. smaller $N-N$ bond energy

  2. larger $N-N$ bond energy

  3. low inoziation enthalpy

  4. none of these

Show answer
Correct Option: B
Explanation:

Both $CN^-$ and $N _2$ have the same number of electrons but $N _2$ is more stable and chemically inert. This is because $N _2$ has a very high bond energy because of the presence of a triple bond between the two $N$ atoms. Both atoms in $N _2$ have achieved a stable electronic configuration, making the $N _2$ atom highly stable. $CN^-$ also has a triple bond but the bond is polar, unlike $N _2$ in which there is no bond polarity. Therefore, $CN^-$ is less stable and not chemically inert.

Which of the following halide of nitrogen is not explosive in nature?

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. $NCl _3$

  2. $NI _3$

  3. $NBr _3$

  4. $NF _3$

Show answer
Correct Option: D
Explanation:

The only stable halide of nitrogen $NF _3$ is not explosive. The other halides are explosive due to their unstable nature because of much larger sizes.


Hence, the correct option is $D$

Hydride of nitrogen is:

chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

  1. acidic

  2. basic

  3. neutral

  4. none of the above

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Correct Option: B
Explanation:

Hydride of nitrogen is basic due to lone pair of electrons on nitrogen atom. The common hydrides of nitrogen are hydrazine,diazene,ammonia out of which only ammonia is thermally stable.