ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

When chloroform is boiled with NaOH, it gives

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

When CO₂ is made to react with ethyl megnesium iodine, followed by hydrolysis, the product formed is:

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

The alkyl halide molecule on which a nucleophile attacks is called

• Substrate A
• Subsituent B
• Substituted C
• All of these D

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

Which is a good nucleophile?

• F^-1 A
• Cl^-1 B
• Be^-1 C
• I^-1 D

Which of the following compounds on oxidation gives benzoic acid?

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

Dehydrohalogenation of alkyl halides give

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

Which bond is most stable

• C - Cl A
• C - F B
• C - Br C
• C - I 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 responds to +ve iodoform test?

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

Alkyl halides ae 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

Elimination bimolecular reactions involve:

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

Grignard's reagent is

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

On warming with silver powder,chloroform is converted into

• Acetylene A
• Hexachloroethane B
• 1,1,2,2-tetrachloroethane C
• ethylene D

The reaction of alcohol with SOCI₂in the presence of pyridine as catalyst gives

• Acids A
• Acid chloride B
• Alkyl halide C
• Benzene D

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

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

Reactivity of alkyl halides with magnisium is of the order:

• Rl > RBr> RCl > RF A
• RBr > RCl >RF > Rl B
• RCL > RF > Rl > RBr C
• RF >RI >RBr > RII D

Which halide among the following is used as methylating agent?

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

Dehydrohalogenation of alkyl halides produces

• Alcohol A
• Alkane B
• Alkene C
• Alkyne 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

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

Which of the following does not give iodoform test?

• Ethanol A
• Ethanal B
• Acetophenone C
• Bezophenone D

Which is a weak nucleophile

• OH^- A
• Br^- B
• NH₃ C
• CI^- D

Which of the following compounds could be prepared by reacting bromoethane with KCN and then reducing the product

• CH₃CH₃ A
• CH₃CH₂NH₂ B
• CH₃CH₂CH₂NH₂ C
• CH₃CH₂CH₃ D

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

• Nitrobenzene A
• Phenol B
• Chlorobenzene C
• Aniline 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

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

• Electronphilic substitution A
• Electrophilic addition B
• Free radical substitution C
• Nuclephilic substitution D