Tag: amines

Questions Related to amines

Sandmeyer reaction is better than Gattermann reaction because:

chemistry amines chemical reactions of diazonium salts chemical properties of diazonium salts diazonium salts

  1. sandmeyer reaction uses salt of copper while Gattermann reaction uses copper powder.

  2. only one salt is produced in Sandmeyer reaction while Gattermann reaction produces two salts.

  3. sandmeyer reaction gives better yield than Gattermann reaction.

  4. all of the above.

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Correct Option: C
Explanation:

Sandmeyer gives a higher yield.So,it is better than Gattermann reaction.

Which of the reaction would you choose for the most beneficial conversion shown below?
$ArN _2^+X \rightarrow ArCl$

chemistry amines chemical reactions of diazonium salts chemical properties of diazonium salts diazonium salts

  1. Sandmeyer Reaction

  2. Gattermann Reaction

  3. Directly reacting with $HCl$

  4. Both A and B

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Correct Option: A
Explanation:

Sandmeyer and Gattermann reactions are two processes used mostly for the above conversion.But Sandmeyer is more beneficial as it gives a higher yield.

Replacement of diazonium group of fluorine is known as:

chemistry amines chemical reactions of diazonium salts chemical properties of diazonium salts diazonium salts

  1. Gattermann reaction

  2. Sandmeyer reaction

  3. Balz-Schiemann reaction

  4. Etard reaction

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Correct Option: C

3- Amino-2, 3-dimethyl butan-2-ol when treated with $ NaNO _{2}/HCl$ gives product (X). (X) on treatment with $LiAlH _{4}$ forms (Y). (Y) on heating with $conc. H _{2}SO _{4}$ forms (Z). The molecular weight of (Z) is :

chemistry amines chemical reactions of diazonium salts chemical properties of diazonium salts diazonium salts

  1. 81

  2. 82

  3. 83

  4. 84

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Correct Option: D
Explanation:

3- Amino-2, 3-dimethyl butan-2-ol is diazotized with sodium nitrite in presence of HCl at low temperature to obtain 3,3-dimethylbutan-2-one (compound X).
The carbonyl group is then reduced to obtain 3,3-dimethylbutan-2-ol (compound Y). This is followed by dehydration to obtain 2,3-dimethylbut-2-ene (compound Z).

Which of the following compounds will not undergo azo coupling reaction with benzene diazonium chloride?

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

  1. Aniline

  2. Phenol

  3. Anisole

  4. Nitrobenzene

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Correct Option: D
Explanation:

Diazonium cation is weak electrophile and hence it reacts with electron rich compounds containing electron donating groups such as $-OH$, $-NH _2$ and $OCH _3$ groups and not with compounds containing electron withdrawing groups such as $-NO _2$ etc.


Hence,option D is correct.

Which of the following diazonium salt is relatively stable of $0-5^o$C?

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

  1. $CH _3CH _2N\equiv N}^{\oplus}Cl^-$

  2. $CH _3-C(CH _3) _2-N\equiv N}^{\oplus} Cl^-$

  3. $CH _3-N\equiv N}^{\oplus}Cl^-$

  4. $(CH _3) _3C-N\equiv N}^{\oplus}Cl^-$

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Correct Option: C

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

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

  1. ${ CH } _{ 3 }-N\equiv N{ } }^{ \oplus }C{ l }^{ - }$

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

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

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

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Correct Option: D
Explanation:

The $+I$ effect which stabilizes the ${ N }^{ + }$ion is in the following order ${ C } _{ 6 }{ H } _{ 5 }-<{ CH } _{ 3 }-<{ \left( { CH } _{ 3 } \right)  } _{ 2 }-<{ \left( { CH } _{ 3 } \right)  } _{ 3 }$

$\therefore $ The ${ \left{ { \left( { CH } _{ 3 } \right)  } _{ 3 }C-N\equiv N \right}  }^{ + }{ Cl }^{ - }$ is most stable

Which of the following is an Incorrect statement about benzenediazonium chloride?

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

  1. It is prepared by the reaction of aniline with nitrous acid at 273-278 K

  2. It is a colourless crystalline solid

  3. Alkyl diazonium salts are more stable than arenediazonium salts

  4. Benzene diazonium fluoroborate is water insoluble & stable at room temperature

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Correct Option: C

For the successful diazotisation of arylamines, how many mole of mineral acid $(HCl \quad or \quad H _2SO _4 )$ are required for each mole of the amine?

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

  1. 1

  2. 2

  3. 3

  4. 4

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Correct Option: C

In an analytical determination of arsenic, a solution containing arsenious acid, $ H _{3}AsO _{4},$ KI and a small amount of starch is electrolysed. The electrolysis produces free $I _{2}$ from $ I^{-}$ ions and the $ I _{2}$ immediately oxidizes the arsenious acid to hydrogen arsenate ion, $ HAsO _{4}^{2-}.$
$ I _{2}+H _{3}AsO _{3}+H _{2}O \rightarrow 2I^{-} + HAsO _{4}^{2-}+4H^{+}$
When the oxidation of arsenic is complete, the free iodine blue colour. If during a particular run, it takes 96.5 s for a current of 10.0 mA to give an end point (indicated by the blue colour),how many g of arsenic are present in the solution. (As = 75)

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

  1. $ 6.3 \times 10^{-4} g$

  2. $1.26 \times 10^{-4}g$

  3. $ 3.15 \times 10^{-5}g$

  4. $ 6.3 \times 10^{-5}g$

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Correct Option: D