ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

Alkyl halides react with Mg in dry ether to form

• Magnesium halide A
• Grignard's reagent B
• Alkene C
• Alkyne D

Aryl halides are less reactive towards nucleophilic substitution reactions as compared to alkyl halides due to

• The formation of less stable carbonium ion A
• Resonance stabilization B
• Larger carbon-halogen bond C
• The inductive effect D

Steps in SN , reactions are:

• One A
• Two B
• Three C
• Four D

When chloroform is boiled with NaOH, it gives

• Formic acid A
• Trihydroxymethane B
• Acetylene C
• Sodium formate D

In primary alkyl halides, the halogen atom is attached to a carbon which attached to how many carbon atoms?

• Two A
• Three B
• One C
• Four D

• Condensation A
• Electrophilic substitution B
• Free radical substitution C
• Nucleophilic substitution D

Chlorobenzene on heating with aqueous NH₃under pressure in the presence of cuprous chloride gives

• Benzamide A
• Nitrobenzene B
• Aniline C
• Chloroaminobenzene D

• Primary alkyl halide A
• Secondary alkyl halide B
• Tertiary alkyl halide C
• None of these D

The reactivity order of alkyl halides for a particular alkyl group is:

• F >Cl>Br>I A
• Cl>Br>F>l B
• l>Br>Cl>F C
• Br>l>Cl>F D

What is the total number of different chloroethanes, formula C₂H_6-nCl_n, where n can be any integer from 1 to 4

• 4 A
• 6 B
• 7 C
• 8 D

C- X bond is strong in

• CH₃Cl A
• CH₃Br B
• CH₃F C
• CH₃I D

Dehydrohalogenation of alkyl halides give

• Alkanes A
• Alkenes B
• Alkynes C
• Alkdehyde D

Which reaction is example of nucleophilic substitution

• 
  A
• 
  B
• 
  C
• 
  D

Alkyle magnesium halides are known as

• Simon-smith reagent A
• Tollen's reagent B
• Grignard's reagent C
• Barford's reagent D

Grignad reagent is reactive due to

• The presence of halogen atom A
• The presence of Mg atom B
• The polarity of C - Mg bond C
• None of above D

Hydrolysis of Grignard's reagent gives:

• Alcohol A
• Halide B
• Alkyl C
• Alkane D

Which of the following undergoes uncleophilic substitution exclusively by S_N1 mechanism?

• Benzyl chloride A
• Ethyl chloride B
• Chlorobenzene C
• Isopropyl choride D

Unpleasant smell of carbylamine is obtained when chloroform and alcoholic KOH are heated with

• Any aromatic amine A
• Any primary amine B
• Any amine C
• Any aliphatic amine D

The general formula of alkyl halides is

• C_nH_2nX A
• C_nH_2n-1X B
• C_nH_2n+1X C
• C_nH_2n-2X D

Butanenitrile is formed by reaction of KCN with

• Propyl alcohol A
• Butyl chloride B
• Butyl alcohol C
• Propyl Chloride D

When CO₂is made to react with ethyl magnesium iodide, followed by acid hydrolysis, the product formed is

• Propane A
• Propanoic acid B
• Propanal C
• Propanol D

Both E₁and E₂mechanism can be shown by

• 1° - RX A
• 2° - RX B
• 3° - RX C
• None of these D

Benzene reacts with chlorine to form benzene hexachloride in presence of

• Nickel A
• AlCl₃ B
• Bright sunlight C
• Zinc D

Tetrabromoethane on treatment with alcoholic zinc gives

• Ethylbromide A
• Ethane B
• Ethene C
• Ethyne D

Most reactive halide towards S_N1 reaction is

• n-Butyl chloride A
• sec-Butyl chloride B
• tert-Butyl choride C
• Allyl chloride D

The final product formed by distilling ethyl alcohol with excess of Cl₂ and Ca(OH)₂is

• CH₃CHO A
• CCl₃CHO B
• CHCl₃ C
• (CH₃)₂O D

The alkyl halide is converted into an alcohol by

• Addition A
• Substitution B
• Dehydrohalogenation C
• Elimination D

Hydrolysis of Grignard's reagent yields

• Alcohol A
• Aldyhyde B
• Ester C
• Alkane D

The reactivity order of alkyl halides for a paricular alkyl group is

• Fluoride > chloride > bromide > iodide A
• Chloride > bromide > fluoride > iodide B
• Iodide > bromide > chloride > fluoride C
• Bromide > iodide > chloride > fluoride D

Alkyl halides in which a halogen atom is bonded to that carbon atom which directly bonded with one hydrogen atom is called

• Primary alkyl halides A
• Secondary alkyl halides B
• Tertiary alkyl halides C
• Quaternary alkyl halides D