ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

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

When chloroform is boiled with NaOH, it gives

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

Both E₁and E₂mechanism can be shown by

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

Which of the following with aqueous KOH will give acetaldehyde?

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

which one of the following is not a nucleophile?

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

The reactivity order of alkyl halides for a particular alkyl group is:

• F >Cl>Br>I A
• Cl>Br>F>l B
• l>Br>Cl>F C
• Br>l>Cl>F D

Cl₂reacts with CS₂in presence of AlCl₃to form

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

C₆H₆Cl₆can be obtained from

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

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

• Ca A
• Na B
• Mg C
• Zn 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

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

Steps in SN , reactions are:

• One A
• Two B
• Three C
• Four D

The reaction of an alkyl halide with RCOOAg produces

• Ester A
• Ether B
• Aldehyde C
• Ketone D

Alkyl halides are reactive :

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

Elimination bimolecular reactions involve:

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

Alkanes may be prepared by the reaction of alkyl halides with

• Alcohol A
• Carboxylic acid B
• Grignard reagents C
• None of these D

Grignard's reagent on treatment with dry CO₂and HCI yields

• Ester A
• Alcohol B
• Carboxylic acid C
• Aldehyde 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

The elimination of hydrogen halide from adjacent carbon atoms is called

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

Which of the following is a nucleophile

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

Cyanoform is ________ acid in nature than the chloroform. The missing word is

• Stronger A
• Weaker B
• Amphoteric C
• Neutral D

When ethyl iodide and n-propyl iodide are allowed to react with sodium metal in ether, the number of alkanes that could be produced is

• Only one A
• Two alkanes B
• Three alkanes C
• Four alkanes 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

Ethyl bromide on treatment with alcoholic KOH gives

• Ethylene A
• Ethanol B
• Acetic Acid C
• Ethane D

Which one of the following in mainly responsible for depletion of ozone layer?

• Methane A
• Carbon dioxide B
• Water C
• chloroflurocarbons D

By simply reacting Grignand's reagent with water we get

• An alkane A
• Higher alkane B
• An alkene C
• An alkyne 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

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