ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

SN2 reaction can be best carried out with

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

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

Primary carbon attaches with other hydrogen atoms directly:

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

When alkyl halide is heated with aqueous solution of ammonia at 100°C the major product is

• Primary amine A
• Secondary amine B
• Tertiary amine C
• Mixture of amines and salt D

Which of the following with aqueous KOH will give acetaldehyde?

• 1, 2-Dichloroethane A
• 1,1-Dichloroethane B
• Chloracetic acid C
• Ethyl chloride 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

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

S_N1 reaction of alkylhalides leads to

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

The alkyl halide is converted into an alcohol by

• Addition A
• Substitution B
• Dehydrohalogenation C
• Elimination 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

Tetrabromoethane on treatment with alcoholic zinc gives

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

Which one of the following is not a nuclelphile

• H₂O A
• H₂S B
• BF₃ C
• NH₃ 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

When chloroform is boiled with NaOH, it gives

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

Ethyl alcohol gives ethyl chloride with the help of

• SOCl₂ A
• NaCl B
• Cl₂ C
• KCl D

which one of the following is not a nucleophile?

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

What is the total number of different chloroethanes, formula C₂H_6-nCl_n, where n can be any integer from 1 to 4

• 4 A
• 6 B
• 7 C
• 8 D

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

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

• Electrophilic addition A
• Electrophilic substitution B
• Free radical substitution C
• Nuclophilic addition 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

General formula of alkyl halide is:

• R----X A
• R----OH B
• R------COH C
• R------COOH D

Reation of which with Grignard's reagent gives primary alcohol:

• Formaldehyde A
• Aldehyde B
• Ketones C
• Acetone 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

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

Metal used in the preparation of Grignard's reagent is:

• Ca A
• Na B
• Mg C
• Zn D

2-Bromopentane is heated with potassium ethoxide in ethanol . The major product obtained is

• 2-Ethoxypentane A
• Pent-1-ene B
• cis-Pent-2-ene C
• trans-Pent-2-ene D

DDT is formed from

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

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

• 
  A
• 
  B
• 
  C
• 
  D