Tag: introduction to diazonium salts

Questions Related to introduction to diazonium salts

Which of the following amines will form stable diazonium salt at 273-283 K? 

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

  1. $\displaystyle { C } _{ 2 }{ H } _{ 5 }{ NH } _{ 2 }$

  2. $\displaystyle { C } _{ 6 }{ H } _{ 5 }{ NH } _{ 2 }$

  3. $\displaystyle { C } _{ 6 }{ H } _{ 5 }{ CH } _{ 2 }{ NH } _{ 2 }$

  4. $\displaystyle { C } _{ 6 }{ H } _{ 5 }{ N\left( { CH } _{ 3 } \right) } _{ 2 }$

Show answer
Correct Option: B

Diazonium salts are used at a very lower temperature because:

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

  1. they are poisonous at room temperature

  2. they are highly unstable at room temperature

  3. they are highly volatile at room temperature

  4. none of these

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Correct Option: B
Explanation:

Diazonium salt is used at very low temperature because of the fact that at the higher temperature they are unstable, as at higher temperature $N _2$ can leave out.

Diazonium salts are used:

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

  1. after storing for a few days after preparation

  2. immediately after its preparation

  3. after storing for $2-3$ hours

  4. difficult to prepare commercially

Show answer
Correct Option: B
Explanation:

Diazonium salts are light sensitive and break down under near UV or violet light.This is why it is used immedietly after being prepared so that it does not loses its properties.

What makes diazonium ion one of the best leaving group of organic chemistry? 

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

  1. Half filled electronic configuration of nitrogen atom

  2. High electronegativity of nitrogen atom

  3. Very high stability of dinitrogen molecule in the atmosphere

  4. Weaker $C-N$ bond

Show answer
Correct Option: C
Explanation:

Diazonium ion is one of best leaving group of organic chemistry because of very high stability of dinitrogen molecule in the atmosphere.

What is the molarity of 0.2 N Na2 CO3 solution ?
chemistry amines introduction to diazonium salts structure, preparation and physical properties of diazonium salts diazonium salts

  1. 0.1M

  2. 0M

  3. 0.4M

  4. 0.2M

Show answer
Correct Option: A

Diazomethane was photolysed to generate singlet carbine which was treated with cis-2-butene. The main product(s) of the reaction is/are:

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

  1. cis-1, 2-dimethylcyclopropane

  2. trans-1, 2-dimethylcyclopropane

  3. mixture of $(A)$ and $(B)$

  4. Ethylcyclopropane

Show answer
Correct Option: A
Explanation:

Solution:- (A) cis-$1,2$-dimethylcyclopropane

$\underset{\text{Diazomethane}}{C{H} _{2}-\overset{+}{N}={N}^{-}} \xrightarrow[-N \equiv N]{h \nu} \underset{\text{Singlet carbene} \left( \text{Methylene} \right)}{:C{H} _{2}}$
The addition of methylene would yield trans-$1,2$-dimethylcyclopropane from trans-$2$-butene and cis-$1,2$-dimethylcyclopropane from cis-$2$-butene.

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^{-} $

Show answer
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.

Show answer
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

Show answer
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.