ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

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

Alkyl halides on treatment with aqueous KOH give

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

Replacement of Cl of Chlorobenzene to give phenol requires drastic conditions but chlorine of 2, 4-Dinitrochlorobenzene is readily replaced because

• NO₂makes the electron rich ring at ortho and para positions A
• NO₂withdraws electrons at metaposition B
• NO₂donate electrons at m-position C
• NO₂withdraws electrons at ortho and para position D

Hydrolysis of Grignard's reagent yields

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

Which of the following is a nucleophile

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

Grignard's reagent is

• Alkyl halide A
• Magnesium halide B
• Alkyl magnesium halide C
• Ethereal solution of an alkyl halide D

The rate of E₁reaction depends upon:

• The concentration of substrate A
• The concentration of nucleophile B
• The concentration of substrate as well as nucleophile C
• None of these D

Alkyl halides are considered to be very reactive compounds towards nucleophiles because

• They have an electrophilic carbon A
• They have an electrophilic carbon and a good leaving group B
• They have an electrophilic carbon and a bad leaving group C
• They have a nucleophilic carbon and a good leaving group D

Iodoethane reacts with sodium in ether, the product formed is

• Pentene A
• Propyne B
• Butene C
• Butane 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

The compounds or species in search of electrons are called

• Elctrophiles A
• Nucleophile B
• Nitrities C
• Bases D

Thre rate of S_N2 reaction depends upon the

• Concentration of alkyl halides A
• Concentration of nucleophile B
• Concentration of alkyl halides and nucleophile C
• None of the above D

• 2-bromo-3-methylbutane A
• 3-methyl-2-bromobutane B
• 2-methyl-3-bromobutane C
• All 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 compounds gives trichoromethane on distilling with bleaching power?

• Methanal A
• Phenol B
• Ethanol C
• methanol 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

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

Most reactive halide towards S_N1 reaction is

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

which one of the following is not a nucleophile?

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

1, 3-Dibromopropane reacts with metallic zinc to form

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

Alkyle magnesium halides are known as

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

Which halide among the following is used as methylating agent?

• CH₃l A
• C₂H₅Cl B
• C₂H₅Br C
• C₆H₅Cl D

Alkyl halides on treatment with Zn and HCI gives

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

DDT is formed from

• Benzene and Chlorobenzene A
• Chloral and Chlorobenzene B
• Chloral and Benzene C
• Chlorobenzene and chlorine D

Which responds to +ve iodoform test?

• Butanol-1 A
• Butan-1-al B
• Butanol-2 C
• 2-pentanone D

The elimination of hydrogen halide from adjacent carbon atoms is called

• Dehydrogenation A
• Hydrogenation B
• Dehydrohalogenation C
• Hydrohalogenation D

SN2 reaction can be best carried out with

• Primary alkyl halides A
• Secondary alkyl halides B
• Tertiary alkyl halides C
• All the three D

Which of the following compounds on oxidation gives benzoic acid?

• Chlorophenol A
• Chlorotoluene B
• Chlorobenzene C
• Benzyl chloride D

By reaction Grignard's reagent with the HCHO we get

• 1° - alcohol A
• 2° - alcohol B
• 3° - alcohol C
• All of these D

Hydrolysis of Grignard's reagent gives:

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