Tag: haloalkanes and haloarenes

Quizzes (2) Questions (32)

Questions Related to haloalkanes and 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).

Multiple choice polyhalogen compounds haloalkanes and haloarenes chemistry

Which of the following statements is not correct?

  1. DDT and BHC are not good insecticides because they are highly soluble in water.

  2. DDT and BHC are not good insecticides because they are absorbed by the soil and contaminate root corps.

  3. Aldrin is not a good insecticide because it is not biodegradable.

  4. All of the above are incorrect.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DDT and BHC 

both are good insecticides
since highly soluble in coater.

Multiple choice polyhalogen compounds haloalkanes and haloarenes chemistry

Match the column I with column II.

Columns I  Columns II 
A Carbon tetrachloride  i Paint remover 
B Methylene chloride  ii Refrigerators and air conditioners 
C DDT iii Fire extinguisher 
D Freons iv Non biodegradable insectiside 

  1. A=(ii), (B)=(iii), (C)=(i), (D)=(iv)

  2. A=(i), (B)=(ii), (C)=(iii), (D)=(iv)

  3. A=(iv), (B)=(iii), (C)=(ii), (D)=(i)

  4. A=(iii), (B)=(i), (C)=(iv), (D)=(ii)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A) Carbon tetra-chloride is colorless, non inflammable and is used as a fire extinguisher. 

B) Methylene chloride is used as a paint remover. 
C) DDT is the chlorinated organic and non biodegradable insecticide. 
D) Freons are produced for aerosol propellants, refrigerators and air conditioners. 

Multiple choice polyhalogen compounds haloalkanes and haloarenes chemistry

0.0852 g of an organic halide (A) when dissolved in 2.0 g of camphor, the melting point of the mixture was found to be $167^{\circ}$C. Compound (A) when heated with sodium gives a gas (B). 280 mL of gas (B) at STP weighs 0.375g. What would be 'A' in the whole process? $K _f$ for camphor = 40, m.pt. of camphor = $179^{\circ}$C.

  1. $C _2H _5Br$
  2. $CH _3I$
  3. $(CH _3) _2CHI$
  4. $C _3H _7Br$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\delta$=179-167=12, w=0.0852g, W=2g,Kf= 40 
Moleculer weight of (A)
=$\dfrac{1000\times{Kf}\times{w} }{\delta{T}\times {W}}$
=$\dfrac{1000\times{40}\times{0.0852} }{\delta{12}\times {2}}$
=142
(A) undergoes wortz reaction to form (B) i.e
$(A)\rightarrow{Na} (B)+NaX$
(B) is an alkane say $C _nH _2n+2$
$\therefore$ 280 mL of (B) weighs 0.375 g at NTP
$\therefore$ 22400 mL of (B) weighs 
=$\dfrac{0.375\times{22400}}{280}$
=30 g at NTP
M.wt of (B)=30, 12n+2n+2=30,n=2
Thus (B) is ethane and therefore (A) is $CH _3X$
The m.wt of $CH _3X$=142
At.wt of X=127
$\therefore$ is iodine 
Therefore alkyl halide is $CH _3I$.
This reaction is 
2$CH _3I\xrightarrow[Na]{ether} C _2h _6$
(A)                         (B)

Multiple choice polyhalogen compounds haloalkanes and haloarenes chemistry

Breathing about 900 parts this substance per million parts of air for a short time cause dizziness heart & fatigue headache is-

  1. Methylene choride

  2. Chloroform

  3. Iodoform

  4. Tetra chlorometane
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chloroform is known to have toxic effects when inhaled, including dizziness, fatigue, and heart issues, even at relatively low concentrations.