ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

Which one of the following is not a nuclelphile

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

Which of the following compounds gives trichoromethane on distilling with bleaching power?

• Methanal A
• Phenol B
• Ethanol C
• methanol D

The reaction of 4-bromobenzyl chloride with NaCN in ethanol leads to

• 4-Bromobenzyl cyanide A
• 4-Cyanobenzyl chloride B
• 4-Cyanobenzyle cyanide C
• 4-Bromo 2-cyanobenzyl chloride D

The order of reactivity for a given halogen in Grignard's reagent is:

• CH₃X > C₂H₅X > C₃H₄X > C₄H₄X A
• C₂H₅X > C₃H₇X > C₄H₅X > CH₄X B
• C₃H₇X > C₄H₇X > CH₃X > C₂H₅X C
• C₄H₄X > C₃H₇X > C₂H₅X > CH₄X D

Alkyl halides are reactive :

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

Grignard's reagent on treatment with chloramine give

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

Hydrolysis of Grignard's reagent yields

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

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

Carbon atom holding halogen in aryl halides is

• sp²-hybridesed A
• sp³-hybridesed B
• sp-hybridesed C
• sp³d-hybridesed D

C- X bond is strong in

• CH₃Cl A
• CH₃Br B
• CH₃F C
• CH₃I D

How many monochlorobutanes will be possible on chlorination of n-butane?

• 1 A
• 2 B
• 3 C
• 5 D

Reaction of ethylamine with chloroform in alcoholic KOH produces

• CH₃OH A
• CH₃NC B
• C₂H₅NC C
• C₂H₅CN D

E₁mechanism is generally shown by

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

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

Grignard reagent is not prepared in aqueous medium but prepared in ether medium because

• The reagent is highly reactive in ether A
• The reagent does not react with water B
• The reagent becomes inactive in water C
• The reagent reacts with water D

1, 3-Dibromopropane reacts with metallic zinc to form

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

Tetrabromoethane on treatment with alcoholic zinc gives

• Ethylbromide A
• Ethane B
• Ethene C
• Ethyne 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

The order of reactivity of an alkyl halide (R-X) for a particular alkyl group is

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

When alkyl halides are heated with aqueous solution of ammonia at about 100°C, amines are formed. This reaction is known as

• Williamsons synthesis A
• GHoffmans reaction B
• Wurtz reaction C
• Clemensen reaction D

Elimination bimolecular reactions usually obey

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

Butanenitrile is formed by reaction of KCN with

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

To get DDT, chlorobenzene has to react with one of the following compound in the presence of conc.H₂SO₄

• Trichloroethane A
• Dichloroacetone B
• Dichloroacetaldehyde C
• Trichloroacetealdehyde D

The elimination of hydrogen halide from adjacent carbon atoms is called

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

If carbon dioxide is bubbled through solution of Grignard's reagent in ether and the resultant product is reacted with hydrochloric acid, it gives

• An alkane A
• Al alcohol B
• A carboxylic acid C
• An aldehyde 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 good living gorup B
• They have an electrophilic carbon and bad living group C
• They have an nucleophilic carbon and good living gorup D

Grignard's reagent on treatment with carbonyl compounds yield

• Pheonol A
• Alcohol B
• Alkane C
• None of these D

The chloroform reacts with NaOH to give

• CH₃COONa A
• Sodium oxalate B
• CH₃OH C
• HCOONa D