Tag: ddt

Questions Related to ddt

In the following reaction, identify the compound A.
$3CH _3-CH _2-OH+A\rightarrow 3C _2H _5-Cl+H _3PO _3$.

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. $PCl _3$

  2. $PCl _5$

  3. $POCl _3$

  4. $H _2PO _2$

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Correct Option: A
Explanation:

A is $PCl _3$ in the above reaction.
$3CH _3-CH _2-OH+PCl _3\rightarrow 3C _2H _5-Cl+H _3PO _3$
Hence option A is corrcet.

By the action of $PCl _3$ or $PCl _5$ with alcohols alkyl halides and a by product $HCl$ is formed.The byproduct HCl is absorbed by using :

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. $Et _3N,C _5H _5N$

  2. $Et _2NH,C _5H _5N$

  3. $Et _NH _2,C _5H _5N$

  4. $Et _3N,C _6H _5N$

Show answer
Correct Option: A
Explanation:

By the action of $PCl _3$ or $PCl _5$ with alcohols alkyl halides and a
by product $HCl$ is formed.The byproduct $HCl$ is absorbed by using Triethyl amine($Et _3N$),pyridine($C _5H _5N$) which are bases and neutralise the acid like $HCl$ and $HBr$ etc.

Trimethyl amine used for _______ in  the preparation of alkyl halide from alchohol and phosphorous halide.

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. the absorption of hydrogen halide

  2. the release of Hydrogen halide

  3. as the catalyst

  4. none

Show answer
Correct Option: A
Explanation:

Trimethyl amine and pyridine used for the absorption of hydrogen halide.in  the preparation of alkyl halide from alchohol and phosphorous halide.As these two are bases which can neutralize the acids like $HCl$ and $HBr$
Hence option A is correct.

What is the product formed when $CH _3CH _2CH _2CH _2-OH$ is reacted with $PCl _3$ in presence of trimethyl amine?

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. $CH _3CH _2CH _2CH _2-Cl$

  2. $CH _3CH(CH _3)CH _2CH _2-Cl$

  3. $CH _3CH _2C(CH _3) _2CH _2-Cl$

  4. $CH _3CH _2CH _2CH _2CH _2CH _2-Cl$

Show answer
Correct Option: A
Explanation:

When Alcohol reacts with $PCl _{3}$ in presence of Trimethyl Amine. It is a nucleophile substitution halogenation reaction replaces $OH^{-}$  with $Cl^{-}$  

   $CH _{3}CH _{2}CH _{2}CH _{2} - OH\overset{PCl _{3}}{\rightarrow} CH _{3}CH _{2}CH _{2}CH _{2} - Cl $

$3C _2H _5OH+A\rightarrow C _2H _5Br+H _3PO _3$.Which of the following is A ?

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. $PBr _3$

  2. $PBr _5$

  3. $POBr _3$

  4. None of the above

Show answer
Correct Option: A
Explanation:

The reagent used in the above reaction is $PBr _3$
$3CH _3-CH _2-OH+PBr _3\rightarrow 3C _2H _5-Cl+H _3PO _3$
Hence option A is correct.

$CH _3CH _2C(CH _3) _2CH _2-OH+PCl _3\rightarrow A+H _3PO _4$. In the above reaction which of the following is A?

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. $CH _3CH _2C(CH _3) _2CH _2-Cl$

  2. $CH _3CH _2CH(CH _3)CH _2-Cl$

  3. $CH _3CH _2CH _2CH _2-Cl$

  4. $CH _3CH(CH _3)C(CH _3) _2CH _2-Cl$

Show answer
Correct Option: A
Explanation:

$CH _3CH _2C(CH _3) _2CH _2-OH+PCl _3\rightarrow CH _3CH _2C(CH _3) _2CH _2-Cl+H _3PO _4$
So in the above reaction A is $CH _3CH _2C(CH _3) _2CH _2-Cl$
Hence option A is correct.

Consider the following reaction:
$R-OH+PX _5\rightarrow R-X+B+HX$ 
What is B?
preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. $HPOX _3$

  2. $H _3PO _2$

  3. $H _3PO _3$

  4. $POX _3$

Show answer
Correct Option: D
Explanation:

B is $ \displaystyle POX _3$.
For example, when ethyl alcohol is refluxed with $ \displaystyle PCl _5$, ethyl chloride, HCl and phosphorous oxy chloride is obtained.
$ \displaystyle CH _3-CH _2-OH +PCl _5 \to CH _3-CH _2-Cl+POCl _3+HCl$

Bases like tri-ethyl amine and pyridine are used to:

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. mop up the acidic byproduct

  2. crystallize alkyl halide

  3. evaporate alkyl halide

  4. none

Show answer
Correct Option: A
Explanation:

Bases like tri-methyl amine and pyridine are used to mop up the acidic byproduct and make it neutral.
Hence option A is correct.

Alkyl bromide is prepared by heating alcohol with ______ phosphorus in the presence of bromine gas.

preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

  1. black

  2. white

  3. red

  4. none of these

Show answer
Correct Option: C
Explanation:

Alkyl Bromide is prepared by heating alcohol with Red phosphorous in the presence of Bromine gas.

$CH _3-OH \xrightarrow{Red\ P/Br _2} CH _3-Br$

In fire extinguishers, which of the following is used?

carbon tetrachloride ddt preparation of haloalkanes halogen derivatives

  1. $CHCl _{3}$

  2. $CS _{2}$

  3. $CCl _{4}$

  4. $CH _{2}Cl _{2}$

Show answer
Correct Option: C
Explanation:

Chloroform is used as solvent and as anaesthetic.
$CCl _4$ is used as fire extinguisher.
$CH _2Cl _2$ is used as paint removing.