ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

Iodoethane reacts with sodium in ether, the product formed is

• Pentene A
• Propyne B
• Butene C
• Butane D

Best medhod of preparation of alkyl halide from alcohals is by its reaction with:

• HX A
• SOCl₂ B
• Px₅ and PX₃ C
• All 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

Most reactive halide towards S_N1 reaction is

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

When primary amine reacts with chloroform in ethanolic KOH, then the product is

• An isocyanide A
• An aldehyde B
• A cyanide C
• An alcohol D

Among the following the most reactive towards alcoholic KOH is

• CH₂= CHBr A
• CH₃COCH₂CH₂Br B
• CH₃CH₂Br C
• CH₃CH₂CH₂Br 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

Grignard reagent is prepared by the reaction of magnesium metal with alkyl halide in the presence of

• Alcohol A
• Water B
• Suephuric acid C
• Dry ether D

• NH₃ HCl A
• KCN in C₂H₅OH NaOH B
• KCN in C₂H₅OH HCl C
• HCN NaOH D

Primary carbon attaches with other hydrogen atoms directly:

• One A
• Two B
• Three C
• At least one or more than it 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

Which of the following reacts with chloroform and base to form phenyl isocynaide?

• Nitrobenzene A
• Phenol B
• Chlorobenzene C
• Aniline D

Which represents nucleophilic aromatic substitution reaction?

• Reaction of benzene with Cl₂in sunlight A
• Benzyl bromide hydrolysis with water B
• Reaction of NaOH with dintrofluoro benzene C
• Sulphonation of benzene D

Which of the following is a nucleophile

• OH A
• CH(CH₃)₃ B
• CH₃⁺ C
• CH₃CH₂CH₃ D

What is the total number of different chloroethanes of formula C₂H_6-nCl_npossible (n may be 1 to 6)

• 6 A
• 8 B
• 9 C
• 10 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

Catalyst in the reaction ROH + SOCl₂-------> RCL+SO₂+HCl is:

• ZnCl₂ A
• Pyridine B
• H₂SO₄ C
• Either D

Alkyl halides are reactive :

• High A
• Medium B
• Less C
• Least D

Hydrolysis of Grignard's reagent yields

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

When carbon dioxide is passed through the R - Mg - X is produced

• Any carboxylic acid A
• Propanoic acid B
• Propanedioic acid C
• None of these 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

Which of the following chlorocompounds is heat easily hydrolysed by hydorxide ion to give the product indicated

• 
  A
• 
  B
• 
  C
• 
  D

Alkyl halides on treatment with aqueous KOH give

• Phenol A
• Alcohol B
• Aldehyde C
• Ketone D

Electronegativity order of alkyl halides is:

• Rl > RBr > RCl > RF A
• Rbr > RCl > RF >Rl B
• RCl > RF >Rl > RBr C
• RF >Ri > RBr >RII D

E₁mechanism is generally shown by

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

CFCs undergo homolytic fission by uv light in the stratosphere which radical could result from this irradiations of CHCICF₂Cl.

• CHF Cl C FCl A
• CH Cl CF₂Cl B
• CHF CF₂Cl C
• C FCl CF₂Cl D

Hydrolysis of Grignard's reagent gives:

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

When metallic sodium in ether is heated with ethyl chloride, which alkane is formed

• Propane A
• Ethane B
• Iso-butane C
• N-butane D

Which bond is most stable

• C - Cl A
• C - F B
• C - Br C
• C - I 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