ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

The alkyl halide is converted into an alcohol by

• Addition A
• Substitution B
• Dehydrohalogenation C
• Elimination D

SN₂reactions can be best carried out with:

• Prl. alkyl halide A
• Sec. Alkyl halide B
• Ter. Alkyl halide C
• All of three D

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

• Ca A
• Na B
• Mg C
• Zn D

The rate of E₁reaction depends upon:

• The concentration of substrate A
• The concentration of nucleophile B
• The concentration of substrate as well as nucleophile C
• None of these D

Both E₁and E₂mechanism can be shown by

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

Grignard 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 them D

Which of the following does not give iodoform test?

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

The compounds or species in search of electrons are called

• Elctrophiles A
• Nucleophile B
• Nitrities C
• Bases D

Which one of the following is not a nuclelphile

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

Grignard's reagent on treatment with carbonyl compounds yield

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

Which one of the following is not a nucleophile

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

Elimination bimolecular reactions usually obey

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

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

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

If Grignard reagent is allowed to react with another alkyl halide the main product is

• An alkane A
• Cyclo alkane B
• Alkyne C
• An alkene 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

Which bond is most stable

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

Any other aldehyde except formaldehyde on reaction with Grignard's will produce

• Secondary alcohol A
• Primary alcohol B
• Tertiary alcohol C
• Aromatic alcohol 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 on treatment with aqueous KOH give

• Phenol A
• Alcohol B
• Aldehyde C
• Ketone D

Which responds to +ve iodoform test?

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

Which of the following alkyl halides is used as a mathylating agent

• CH₂H₅l A
• CH₃l B
• C₂H₅Pr C
• C₂H₅Cl D

Reduction of alkyl halides give

• Alkanes A
• Alkenes B
• Ketones C
• Ether 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

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

Grignard's reagent is

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