Tag: p- block elements-ii

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

Alkali metals dissolve in liquid ammonia and produces _______.

  1. deep blue solution

  2. a solution which are conducting in nature

  3. red coloured solution
  4. Both $1$ and $2$
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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


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

  1. Bleaching agent

  2. Antisepics

  3. Restoring colour of old paintings

  4. Rocket Propellant
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hydrazine (N2H4) reacts with hydrogen peroxide as a rocket propellant, producing energy and gases for thrust. The equation suggests an oxidation reaction where H2O2 acts as an oxidizer. H2O2 is not used as bleaching agent, antiseptic, or for restoring paintings in this context.

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

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

  1. smaller $N-N$ bond energy
  2. larger $N-N$ bond energy

  3. low inoziation enthalpy

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

Which of the following halide of nitrogen is unstable in nature?

  1. $NCl _3$
  2. $NBr _3$
  3. $NI _3$
  4. $NF _3$
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Nitrogen has very small size as compared to the halogens, which have much larger sizes. Due to this, they can not remain bonded to the nitrogen atom and hence are highly unstable. $NF _3 $ is stable because fluorine and nitrogen have comparable sizes and electronegativity.

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

In the commercial preparation of dinitrogen by the liquefaction and fractional distillation,dinitrogen is obtained in:

  1. liquid form

  2. gaseous form

  3. mixture of liquid and gases

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the commercial preparation of dinitrogen by the liquefaction and fractional distillation,dinitrogen is obtained in gaseous form.