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

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 good living gorup B
• They have an electrophilic carbon and bad living group C
• They have an nucleophilic carbon and good living gorup D

Hydrolysis of Grignard's reagent yields

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

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

Grignard's reagent was prepared in:

• 1900 A
• 1910 B
• 1920 C
• 1930 D

Each of the following compounds is effective as a refrigerant. The release of which one of these causes the greatest depletion of the ozone layer

• CCl₂F₂ A
• CH₃OCH₃ B
• CH₃CHF₂ C
• CH₃CH₂CH₃ 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

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

Chlorobenzene on heating with aqueous NH₃under pressure in the presence of cuprous chloride gives

• Benzamide A
• Nitrobenzene B
• Aniline C
• Chloroaminobenzene 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

Elimination bimolecular reactions involve:

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

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

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

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

• 1 A
• 2 B
• 3 C
• 5 D

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

Cl₂reacts with CS₂in presence of AlCl₃to form

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

Reaction of ethylamine with chloroform in alcoholic KOH produces

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

Alkyl halides react with lithium dialkyl copper reagents to give

• Alkenes A
• Alkyl copper halides B
• Alkanes C
• Alkenyl halides D

1-Chlorobutane on reaction with alcoholic potash gives

• But 1-ene A
• Butan-1-ol B
• But-2-ene C
• Butan-2-ol D

Both E₁and E₂mechanism can be shown by

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

Gammexane is

• Chlorobenzene A
• Benzyl chloride B
• Brommobenzene C
• Benzene hexachloride D

Which one of the following is not a nuclelphile

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

C₆H₆Cl₆can be obtained from

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

Which bond is most stable

• C - Cl A
• C - F B
• C - Br C
• C - I 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

With the increase in size of halogen atom the reactivity of an alkyl halide

• Increases A
• Decreases B
• Remain constant C
• None of these D

• Electrophilic substitution A
• Free radical reduction B
• Isomerisation C
• Nucleophilic substitution D