ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

If Grignard reagent is allowed to react with another alkyl halide the main product is

• An alkane A
• Cyclo alkane B
• Alkyne C
• An alkene D

Which of the following alkyl halides is used as a mathylating agent

• CH₂H₅l A
• CH₃l B
• C₂H₅Pr C
• C₂H₅Cl D

S_N1 reaction of alkylhalides leads to

• Retention of configuration A
• Recemisation B
• Inversion of configuration C
• None of these D

Grignard's reagent on treatment with chloramine give

• Acetamide A
• Primary amice B
• Secondary amice C
• Urea D

Action of Zn with alkyl halides in the presence of an inert solvent forms higher alkanes. This reaction is known as

• Wurtz reaction A
• Frankland's reaction B
• Cannizaro reaction C
• Kalobe's reaction D

Reduction of alkyl halides give

• Alkanes A
• Alkenes B
• Ketones C
• Ether D

1, 3-Dibromopropane reacts with metallic zinc to form

• Propene A
• Propane B
• Cyclopropane C
• Hexane D

Cyanoform is ________ acid in nature than the chloroform. The missing word is

• Stronger A
• Weaker B
• Amphoteric C
• Neutral D

Alkyl halides on treatment with metallic Na give

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

Both E₁and E₂mechanism can be shown by

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

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

For which mechanisms, the first step involved is the same:

• E₁ and E₂ A
• E₂and SN₂ B
• E₂ and E₁ C
• E1 and SN₁ 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

Ethyl bromide is formed by the reaction of HBr with

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

Alkyl halides are reactive :

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

Cl₂reacts with CS₂in presence of AlCl₃to form

• CHCl₃ A
• CCl₄ B
• C₂H₅Cl C
• C₂H₆ D

Elimination bimolecular reactions usually obey

• First order kinetics A
• Second order kinetics B
• Third order kinetics C
• Zero order kinetics D

Which of the following compounds will form a hydrocarbon on reaction with Grignard reagent

• A ketone A
• An aldehyde B
• An ether C
• Water 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

A carbon atom carrying a postitive charge and attached to three other atoms of groups is called

• Caronium ion A
• Carbanion B
• Oconium ion C
• Carba ion D

A set of compounds in which reactivity of halogen atom in the ascending order is

• Chlorobenzene, vinyl chloride, chloroethane A
• Chloroethane, chlorobenzene, vinyl chloride B
• Vinyl chloride,chlorobenzene chloroethane C
• Vinyl chloride, chloroethane,chlorobenzene D

When formaldehyde is added to Grignard reagent we get

• Aldehyde A
• Acetone B
• Primary alcohol C
• Secondary alcohol D

Alcohol can be prepared from Grignard's reagent with an aldehyde: If we start with formaldehyde the product alcohol with be

• Primary A
• Secondary B
• Territory C
• Aromatic D

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

C₆H₆Cl₆can be obtained from

• HCl and Benzene A
• Cl₂and Benzene and AlCl₃ B
• Cl₂and Benzene in diffused light C
• NaOCl and Benzene D

A reaction in which an atom or a group of atoms replaces an atom or a group of atoms in the molecule of a substance is known as

• Addition reaction A
• Condensation reaction B
• Elimination reaction C
• Substitution reaction D

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

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