Tag: amines

Questions Related to amines

Which of the following diazonium salt is relatively stable of $0-5^\circ C$- :

chemistry amines introduction to diazonium salts structure, preparation and physical properties of diazonium salts diazonium salts

  1. $CH _{3}CH _2N\equiv N\left. \right } ^\oplus Cl^{-} $

  2. $CH _{3}-C(CH _{3}) _{2}-N\equiv N\left. \right } ^\oplus Cl^{-} $

  3. $CH _{3}-N\equiv N\left. \right } ^\oplus Cl^{-} $

  4. $(CH _{3}) _{3}C-N\equiv N\left. \right } ^\oplus Cl^{-} $

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Correct Option: C
Explanation:

The diazonium salt  $CH _{3}-N\equiv N\left.  \right } ^\oplus Cl^{-}$ obtained by treatment of methylamine with nitrous acid is relatively stable at $0-5^\circ C$.

Which of the following diazonium salt is relatively stable at $\displaystyle 0-5^{\circ}$C?

chemistry amines introduction to diazonium salts structure, preparation and physical properties of diazonium salts diazonium salts

  1. $\displaystyle CH _{3}-N\equiv N \left. \right }^{\oplus }Cl^{-}$

  2. $\displaystyle CH _{3}C\left ( CH _{3} \right )-N\equiv N \left. \right }^{\oplus }Cl^{-}$

  3. $\displaystyle C _{6}H _{5}-N\equiv N \left. \right }^{\oplus }Cl^{-}$

  4. $\displaystyle \left ( CH _{3} \right ) _{3}C-N\equiv N \left. \right }^{\oplus }Cl^{-}$

Show answer
Correct Option: C
Explanation:

Diazonium salts obtained from aliphatic primary amines are unstable. Those obtained from aromatic primary amines are relatively stable.
Benzene diazonium chloride $(\displaystyle C _{6}H _{5}-N\equiv N \left.  \right }^{\oplus }Cl^{-})$ is obtained from aromatic primary amine. Hence, it is relatively stable.

Which of the following statements are correct? 

chemistry amines introduction to diazonium salts structure, preparation and physical properties of diazonium salts diazonium salts

  1. Aryldiazonium ions are more stable than alkyldiazonium ions.

  2. Electron release from the ortho- and para-positions of the ring stabilises the aryldiazonium ion.

  3. The increased stability of aryldiazonium is due to the great difficulty of forming $\displaystyle { Ar }^{ \oplus }$ as compared to $\displaystyle { R }^{ \oplus }$.

  4. Alkyldiazonium is more stable than aryldiazonium ion.

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Correct Option: A,B,C

Arrange the following resonating structure according to their contribution towards resonance hybrid?
(a) $CH _2=\overset {\oplus}{N}=\overset {\ominus}{N}$ (b) $\overset {\ominus}{C}H _2-N=\overset {\oplus}{N}:$ (c) $\overset {\oplus}{C}H _2-\underset {. .}{N}=\overset {\ominus}{N}$ (d) $\overset {\ominus}{C}H _2-\overset {\oplus}{N}\equiv \overset {. .}{N}$

chemistry amines introduction to diazonium salts structure, preparation and physical properties of diazonium salts diazonium salts

  1. a > d > c > b

  2. b > a > c > d

  3. a > c > b > d

  4. d > a > b > c

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Correct Option: A
Explanation:
The correct order of the contribution of resonating structure towards resonance hybrid is
$\displaystyle a (CH _2=\overset {\oplus}{N}=\overset {\ominus}{N}) > d (\overset {\ominus}{C}H _2-\overset {\oplus}{N}\equiv \overset {. .}{N}) > c (
\overset {\oplus}{C}H _2-\underset {. .}{N}=\overset {\ominus}{N}
) > b (\overset {\ominus}{C}H _2-N=\overset {\oplus}{N}:)$
a and d have higher contribution as they have less charge separation.
b and c have lower contribution as they have more charge separation.