ECAT Pre Engineering Chemistry Chapter 21 MCQ Test With Answer

Ethyl alcohol gives ethyl chloride with the help of

• SOCl₂ A
• NaCl B
• Cl₂ C
• KCl D

Which of the following compounds will form a hydrocarbon on reaction with Grignard reagent

• A ketone A
• An aldehyde B
• An ether C
• Water D

By simply reacting Grignand's reagent with water we get

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

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

Tertiary alkyl halides are practically inert to substitution by S_N2 mechanism because of

• Onsolubility A
• Instability B
• Inductive effect C
• Steric hindrance D

On warming with silver powder,chloroform is converted into

• Acetylene A
• Hexachloroethane B
• 1,1,2,2-tetrachloroethane C
• ethylene D

Ethyl bromide on treatment with alcoholic KOH gives

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

Which represents nucleophilic aromatic substitution reaction?

• Reaction of benzene with Cl₂in sunlight A
• Benzyl bromide hydrolysis with water B
• Reaction of NaOH with dintrofluoro benzene C
• Sulphonation of 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

Which of the following does not give iodoform test?

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

Most reactive halide towards S_N1 reaction is

• n-Butyl chloride A
• sec-Butyl chloride B
• tert-Butyl choride C
• Allyl chloride D

SN₂ reaction has order of reaction :

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

The general formula of alkyl halides is

• C_nH_2nX A
• C_nH_2n-1X B
• C_nH_2n+1X C
• C_nH_2n-2X D

• 2-bromo-3-methylbutane A
• 3-methyl-2-bromobutane B
• 2-methyl-3-bromobutane C
• All of these D

The alkyl halide is converted into an alcohol by

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

Which reaction is example of nucleophilic substitution

• 
  A
• 
  B
• 
  C
• 
  D

Alkyl halides react with Mg in dry ether to form

• Magnesium halide A
• Grignard's reagent B
• Alkene C
• Alkyne D

Which of the following reacts with chloroform and base to form phenyl isocynaide?

• Nitrobenzene A
• Phenol B
• Chlorobenzene C
• Aniline D

Halogens on treating with silver salts of acids give

• Alcohol A
• Ester B
• Phenol C
• Alkyl halide 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

Which one of the following is not a nucleophile

• H₂O A
• H₂S B
• BF₃ C
• NH₃ 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

When an alcohol reacts with SOCI₂an alkyl halide is formed. What are two other products

• SO₂and HCI A
• SI₂and H₂O B
• HCI and H₂O C
• H₂S and HCI 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

C₆H₆Cl₆can be obtained from

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

• Electrophilic addition A
• Electrophilic substitution B
• Free radical substitution C
• Nuclophilic addition D

A set of compounds in which reactivity of halogen atom in the ascending order is

• Chlorobenzene, vinyl chloride, chloroethane A
• Chloroethane, chlorobenzene, vinyl chloride B
• Vinyl chloride,chlorobenzene chloroethane C
• Vinyl chloride, chloroethane,chlorobenzene 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

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 the above D