Tag: reactions of haloarenes

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Questions Related to reactions of haloarenes

Multiple choice reactions of haloarenes haloalkanes and haloarenes chemistry

Which of the following Grignard reagent can be prepared? 

  1. $Br-Mg-{CH} _{2}-{CH} _{2}-{CH} _{2}O-H$
  2. $Br-Mg-{CH} _{2}-{CH} _{2}-SH$
  3. $BrMg-{CH} _{2}-{CH} _{2}-{NH} _{2}$
  4. $BrMg - CH _2- CH _2 - \underset{CH _3}{\underset{|}{N} -} CH _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Grignards reagent form via the reaction of an alkyl or aryl halide with magnesium metal.The reaction is conducted by adding the organic halide to a suspension of magnesium in an ethyal solugnt,which produce the reaction proceeds through a single electron transfer as:
$R-X+mg\longrightarrow R-X^-+Mg^+$
$R-X^-\longrightarrow R+X^-$
$R+Mg^+\longrightarrow RMg^+$
$RMg^++X^-\longrightarrow RMgX$
Thus,by the above way of preparing grignard reagent,compounds with carbonyl group $(C=O)$,$-SH$ group and $-NH _2$ group cannot be prepared .
Multiple choice reactions of haloarenes haloalkanes and haloarenes chemistry

In which of the following reactions, products are not correctly matched in:

  1. $RMgX +{CO _{2}}\xrightarrow[(ii)H^{\bigoplus }]{(i)CO _{2}}$Carboxylic acid
  2. $RMgX + C _{2}H _{5}OH \rightarrow$ Alkane
  3. $RMgX+CH _{3}CH _{2}Cl\rightarrow$ Alkene

  4. <span class="MathJax_Preview">
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Reaction:
$RMgX+CH _{3}CH _{2}Cl\rightarrow R-R$ alkane.

Multiple choice reactions of haloarenes haloalkanes and haloarenes chemistry

Propane dithioic acid is prepared by which of the following reactions, followed by hydrolysis:

  1. ${C} _{3}{H} _{7}MgBr+{CS} _{2}$
  2. ${C} _{2}{H} _{5}MgBr+{CS} _{2}$
  3. ${C} _{3}{H} _{7}MgBr+{SO} _{2}$
  4. ${C} _{2}{H} _{5}MgBr+{SO} _{3}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Propane dithioic acid is prepared by the reaction of the following, followed by hydrolysis of ${C} _{2}{H} _{5}MgBr+{CS} _{2}$
Hence option B is correct.
Multiple choice reactions of haloarenes haloalkanes and haloarenes chemistry

Which of the following reaction involves copper metal?

  1. Wurtz reaction

  2. Wurtz-Fittig reaction

  3. Ullmann reaction

  4. Frankland reaction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Wurtz & Wurtz-Fittig reactions involve Sodium (Na) metal.


Frankland reaction involves Zinc or Magnesium (Zn or Mg) metal.

Ullmann reaction involves Copper (Cu) metal.

Option C is correct.

Multiple choice reactions of haloarenes haloalkanes and haloarenes chemistry

On reacting with which of the following chemicals sulphur undergoes combination reaction?

  1. metals

  2. nonmetals

  3. acids

  4. alkalies
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

 On reacting with metals and non metals sulphur undergoes combination reaction.
$\displaystyle Fe+S \rightarrow FeS$
$\displaystyle Cl _2+2S \rightarrow S _2Cl _2$
Note:
A combination reaction (also known as a synthesis reaction) is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product).