ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

The elimination of hydrogen halide from adjacent carbon atoms is called

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

Grignard's reagent on treatment with dry CO₂and HCI yields

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

What is the total number of different chloroethanes of formula C₂H_6-nCl_npossible (n may be 1 to 6)

• 6 A
• 8 B
• 9 C
• 10 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

• Primary alkyl halide A
• Secondary alkyl halide B
• Tertiary alkyl halide C
• None of these D

What happens when CCl₄is treated with AgNO₃solution?

• NO₂will be evolved A
• A white ppt. of AgCl will form B
• CCl₄will dissolve in AgNO₃solution C
• Nothing will happen D

Which bond is most stable

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

The reaction of alcohol with SOCI₂in the presence of pyridine as catalyst gives

• Acids A
• Acid chloride B
• Alkyl halide C
• Benzene D

Ethyl bromide is formed by the reaction of HBr with

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

Gammexane is

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

Which halide among the following is used as methylating agent?

• CH₃l A
• C₂H₅Cl B
• C₂H₅Br C
• C₆H₅Cl D

Ethyl chloride on treatment with aqueous alkali gives

• Ethane A
• Ethene B
• Ethanal C
• Ethanol D

By simply reacting Grignand's reagent with water we get

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

C₆H₆Cl₆can be obtained from

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

Replacement of Cl of Chlorobenzene to give phenol requires drastic conditions but chlorine of 2, 4-Dinitrochlorobenzene is readily replaced because

• NO₂makes the electron rich ring at ortho and para positions A
• NO₂withdraws electrons at metaposition B
• NO₂donate electrons at m-position C
• NO₂withdraws electrons at ortho and para position D

Elimination bimolecular reactions usually obey

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

Grignard's reagent was prepared in:

• 1900 A
• 1910 B
• 1920 C
• 1930 D

General formula of alkyl halide is:

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

In which of the following reactions is the inorganic reagent acting as a nucleophile

• 
  A
• 
  B
• 
  C
• 
  D

Catalyst in the reaction ROH + SOCl₂-------> RCL+SO₂+HCl is:

• ZnCl₂ A
• Pyridine B
• H₂SO₄ C
• Either D

Which responds to +ve iodoform test?

• Butanol-1 A
• Butan-1-al B
• Butanol-2 C
• 2-pentanone 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 of the following compounds on oxidation gives benzoic acid?

• Chlorophenol A
• Chlorotoluene B
• Chlorobenzene C
• Benzyl chloride D

An electrophile may be

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

Which one of the following is not a nuclelphile

• H₂O A
• H₂S B
• BF₃ C
• NH₃ D

Alkyl halides on treatment with Zn and HCI gives

• Alkanes A
• Alkenes B
• Alkynes C
• Alcohols D

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