ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

Electronegativity order of alkyl halides is:

• Rl > RBr > RCl > RF A
• Rbr > RCl > RF >Rl B
• RCl > RF >Rl > RBr C
• RF >Ri > RBr >RII D

Alkyl halides are reactive :

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

Which one of the following will have the maximum dipole moment

• CH₃F A
• CH₃Cl B
• CH₃Br C
• CH₃l D

Benzene hexachloride is used as

• Dye A
• Antimaterial drug B
• Antibiotic C
• Insecticide 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

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

An electrophile may be

• Positive A
• Negative B
• Neutral C
• Both c and a D

Which of the following reagent cannot be used for preparing alkyl chloride from alcohol?

• HCl + anhyd. Zncl₂ A
• NaCl B
• PCl₅ C
• SOCl₂ 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

Carbon atom holding halogen in aryl halides is

• sp²-hybridesed A
• sp³-hybridesed B
• sp-hybridesed C
• sp³d-hybridesed D

Ethyl bromide is formed by the reaction of HBr with

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

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

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

Which of the followings is not a nulceophile

• OH^- A
• NH₃ B
• C₂H₅O^- C
• Br₂ D

Ethyl alcohol gives ethyl chloride with the help of

• SOCl₂ A
• NaCl B
• Cl₂ C
• KCl D

SN2 reaction can be best carried out with

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

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

The compounds or species in search of electrons are called

• Elctrophiles A
• Nucleophile B
• Nitrities C
• Bases 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

Grignard's reagent on treatment with dry CO₂and HCI yields

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

S_N1 reaction of alkylhalides leads to

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

When metallic sodium in ether is heated with ethyl chloride, which alkane is formed

• Propane A
• Ethane B
• Iso-butane C
• N-butane 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

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

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

In primary alkyl halides, the halogen atom is attached to a carbon which attached to how many carbon atoms?

• Two A
• Three B
• One C
• Four 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

SN₂reactions can be best carried out with:

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