Q.1: Which of the following is used as a refrigerant?
(a) CFCs
(b) Alcohols
(c) Aldehydes
(d) Ketones
Answer: (a) CFCs
Explanation: Chlorofluorocarbons (CFCs) are widely used as refrigerants due to their stability and non-flammability. They do not react with other substances under normal conditions.
Q.2: Which one of the following compounds will not undergo a nucleophilic substitution reaction easily?
(a) Benzyl chloride
(b) Chlorobenzene
(c) 2-Chlorobutane
(d) 1-Chloropropane
Answer: (b) Chlorobenzene
Explanation: Chlorobenzene has a partial double bond character due to resonance, making the C-Cl bond stronger and less susceptible to nucleophilic substitution.
Q.3: The major product obtained in the reaction of 2-bromobutane with alcoholic KOH is:
(a) 1-butene
(b) 2-butene
(c) Butane
(d) 2,2-dibromobutane
Answer: (b) 2-butene
Explanation: Alcoholic KOH induces dehydrohalogenation, leading to the formation of an alkene. In this case, 2-butene is the major product due to its higher stability compared to 1-butene.
Q.4: Which of the following reactions will produce an alcohol? (a) Hydrolysis of alkyl halides (b) Dehydration of alcohols (c) Oxidation of alkanes (d) Hydrogenation of alkenes
Answer: (a) Hydrolysis of alkyl halides Explanation: Hydrolysis of alkyl halides involves the substitution of the halide group with a hydroxyl group, resulting in the formation of an alcohol.
Q.5: Which of the following is a primary alkyl halide? (a) Isopropyl chloride (b) sec-Butyl chloride (c) tert-Butyl chloride (d) n-Propyl chloride
Answer: (d) n-Propyl chloride Explanation: n-Propyl chloride is a primary alkyl halide because the chlorine atom is attached to a carbon atom that is connected to only one other carbon atom.
Q.6: The compound CCl₃CHO reacts with chlorobenzene in the presence of sulfuric acid to form:
(a) DDT
(b) Chloral
(c) Benzyl chloride
(d) Chloroform
Answer: (a) DDT
Explanation: The reaction between CCl₃CHO (chloral) and chlorobenzene in the presence of sulfuric acid produces DDT (dichlorodiphenyltrichloroethane).
Q.7: Which of the following is not a Freon?
(a) CCl₃F
(b) CCl₂F₂
(c) CHF₃
(d) CH₄
Answer: (d) CH₄
Explanation: Freons are chlorofluorocarbons (CFCs) used as refrigerants. CH₄ (methane) does not contain any chlorine or fluorine atoms and is not considered a Freon.
Q.8: Which of the following compounds can exhibit optical isomerism?
(a) 2-Chlorobutane
(b) 1-Chlorobutane
(c) 2-Bromopropane
(d) 1-Bromopropane
Answer: (a) 2-Chlorobutane
Explanation: 2-Chlorobutane can exhibit optical isomerism because it has a chiral center (a carbon atom attached to four different groups).
Q.9: Which of the following is used as a fire extinguisher?
(a) Carbon tetrachloride
(b) Benzene
(c) Ethanol
(d) Ether
Answer: (a) Carbon tetrachloride
Explanation: Carbon tetrachloride is used as a fire extinguisher because it can suppress flames without being flammable itself.
Q.10: What is the major product when chlorobenzene is heated with NaOH at 300°C under high pressure?
(a) Phenol
(b) Benzene
(c) Aniline
(d) Benzyl alcohol
Answer: (a) Phenol
Explanation: When chlorobenzene is heated with NaOH at 300°C under high pressure, nucleophilic substitution occurs, resulting in the formation of phenol.
Q.11: Which of the following halides undergoes hydrolysis most readily?
(a) CCl₄
(b) SiCl₄
(c) SnCl₄
(d) PbCl₄
Answer: (b) SiCl₄
Explanation: Silicon tetrachloride (SiCl₄) undergoes hydrolysis most readily due to the high reactivity of silicon with water, forming silicic acid and hydrochloric acid.
Q.12: The reaction of an alkyl halide with an aqueous solution of sodium hydroxide is an example of:
(a) Electrophilic substitution
(b) Nucleophilic substitution
(c) Electrophilic addition
(d) Nucleophilic addition
Answer: (b) Nucleophilic substitution
Explanation: In this reaction, the hydroxide ion (a nucleophile) replaces the halide ion in the alkyl halide, resulting in a nucleophilic substitution reaction.
Q.13: The IUPAC name of CH₃-CH₂-CH(Br)-CH₃ is:
(a) 2-Bromobutane
(b) 3-Bromobutane
(c) 1-Bromobutane
(d) 2-Bromopropane
Answer: (a) 2-Bromobutane
Explanation: The correct IUPAC name is 2-Bromobutane because the bromine atom is attached to the second carbon atom in the butane chain.
Q.14: Which of the following is an example of a secondary alkyl halide?
(a) Isobutyl chloride
(b) sec-Butyl chloride
(c) tert-Butyl chloride
(d) n-Butyl chloride
Answer: (b) sec-Butyl chloride
Explanation: In sec-Butyl chloride, the chlorine atom is attached to a secondary carbon atom, which is connected to two other carbon atoms.
Q.15: The compound C₆H₅CH₂Cl on reaction with aqueous KOH gives:
(a) C₆H₅CH₂OH
(b) C₆H₅CHO
(c) C₆H₅COOH
(d) C₆H₅Cl
Answer: (a) C₆H₅CH₂OH
Explanation: Benzyl chloride (C₆H₅CH₂Cl) reacts with aqueous KOH to undergo nucleophilic substitution, forming benzyl alcohol (C₆H₅CH₂OH).
Q.16: Which of the following halides reacts fastest with aqueous KOH?
(a) Methyl chloride
(b) Ethyl chloride
(c) Isopropyl chloride
(d) tert-Butyl chloride
Answer: (d) tert-Butyl chloride
Explanation: tert-Butyl chloride reacts fastest with aqueous KOH due to the formation of a stable tert-butyl carbocation in the reaction mechanism.
Q.17: What is the major product of the reaction between 1-bromo-2-methylpropane and KCN?
(a) 2-Methyl-2-butanenitrile
(b) 2-Methyl-1-butanenitrile
(c) 2-Methylpropane
(d) 2-Methylpropanenitrile
Answer: (b) 2-Methyl-1-butanenitrile
Explanation: The reaction involves nucleophilic substitution where the CN⁻ ion replaces the bromine atom, resulting in 2-Methyl-1-butanenitrile.
Q.18: The reaction of chloroform with alcoholic KOH and aniline produces:
(a) Phenyl isocyanide
(b) Phenol
(c) Benzene
(d) Benzyl alcohol
Answer: (a) Phenyl isocyanide
Explanation: This reaction is known as the Carbylamine reaction, which produces phenyl isocyanide (C₆H₅NC) when aniline reacts with chloroform and alcoholic KOH.
Q.19: Which of the following statements is correct about CFCs?
(a) They are non-toxic and non-flammable.
(b) They deplete the ozone layer.
(c) They are used as refrigerants.
(d) All of the above
Answer: (d) All of the above
Explanation: CFCs (chlorofluorocarbons) are non-toxic, non-flammable, used as refrigerants, and have a significant role in the depletion of the ozone layer.
Q.20: Which of the following is used in the preparation of Teflon?
(a) Vinyl chloride
(b) Ethylene
(c) Tetrafluoroethylene
(d) Styrene
Answer: (c) Tetrafluoroethylene
Explanation: Teflon is prepared by the polymerization of tetrafluoroethylene (C₂F₄).
Q.21: The reaction of ethyl chloride with sodium ethoxide gives:
(a) Ethyl alcohol
(b) Diethyl ether
(c) Ethylene
(d) Acetaldehyde
Answer: (b) Diethyl ether
Explanation: The reaction between ethyl chloride and sodium ethoxide is a Williamson ether synthesis, resulting in the formation of diethyl ether.
Q.22: Which of the following halides does not undergo the Finkelstein reaction?
(a) Chloromethane
(b) Bromoethane
(c) Iodoethane
(d) Fluoroethane
Answer: (d) Fluoroethane
Explanation: The Finkelstein reaction involves the exchange of halides and is not applicable to fluoroethane due to the strong C-F bond.
Q.23: Which of the following will not give a precipitate with AgNO₃?
(a) CH₃Cl
(b) CH₃Br
(c) CH₃I
(d) C₂H₅Cl
Answer: (a) CH₃Cl
Explanation: Methyl chloride (CH₃Cl) does not readily give a precipitate with AgNO₃ because the C-Cl bond is relatively strong and does not ionize easily.
Q.24: Which of the following is an intermediate in the Sandmeyer reaction?
(a) Aryl diazonium salt
(b) Aryl halide
(c) Phenol
(d) Benzene
Answer: (a) Aryl diazonium salt
Explanation: The Sandmeyer reaction involves the conversion of aryl diazonium salts to aryl halides.
Q.25: The reactivity of alkyl halides in a nucleophilic substitution reaction follows the order:
(a) RI > RBr > RCl > RF
(b) RF > RCl > RBr > RI
(c) RCl > RBr > RI > RF
(d) RI > RF > RCl > RBr
Answer: (a) RI > RBr > RCl > RF
Explanation: The reactivity of alkyl halides in nucleophilic substitution reactions decreases with the increase in bond strength, making iodides the most reactive and fluorides the least.
Q.26: The formation of iodoform is not shown by:
(a) Ethanol
(b) Acetone
(c) Ethanal
(d) 2-Propanol
Answer: (a) Ethanol
Explanation: Ethanol does not have the necessary structure (a methyl ketone or a secondary alcohol with a methyl group) to undergo the iodoform reaction.
Q.27: Which of the following compounds will undergo an SN1 reaction most readily?
(a) Methyl chloride
(b) Ethyl chloride
(c) Isopropyl chloride
(d) tert-Butyl chloride
Answer: (d) tert-Butyl chloride
Explanation: tert-Butyl chloride undergoes SN1 reaction most readily due to the formation of a highly stable tertiary carbocation.
Q.28: Which of the following is used as an anesthetic?
(a) Chloroform
(b) Benzene
(c) Ethanol
(d) Toluene
Answer: (a) Chloroform
Explanation: Chloroform (CHCl₃) has been used as an anesthetic due to its ability to depress the central nervous system.
Q.29: Which of the following is an example of a vinyl halide?
(a) Ethyl chloride
(b) Vinyl chloride
(c) Allyl chloride
(d) Propyl chloride
Answer: (b) Vinyl chloride
Explanation: Vinyl chloride (CH₂=CHCl) is an example of a vinyl halide where the halogen atom is directly bonded to an sp² hybridized carbon atom.
Q.30: Which of the following is used in the preparation of Freon-12?
(a) Methane
(b) Ethane
(c) Tetrafluoroethylene
(d) Trichloromethane
Answer: (d) Trichloromethane
Explanation: Freon-12 (CCl₂F₂) is prepared by the fluorination of trichloromethane (chloroform).
Q.31: Which of the following is a non-biodegradable pollutant?
(a) Polyvinyl chloride
(b) Ethanol
(c) Methanol
(d) Acetone
Answer: (a) Polyvinyl chloride
Explanation: Polyvinyl chloride (PVC) is a non-biodegradable pollutant as it is a synthetic polymer that does not decompose naturally.
Q.32: Which of the following is used as an antifreeze in automobile radiators?
(a) Ethylene glycol
(b) Glycerol
(c) Methanol
(d) Acetone
Answer: (a) Ethylene glycol
Explanation: Ethylene glycol is used as an antifreeze due to its ability to lower the freezing point of water.
Q.33: The conversion of an alkyl halide to an alkene using an alcoholic KOH solution is called:
(a) Dehydrohalogenation
(b) Hydrohalogenation
(c) Hydration
(d) Halogenation
Answer: (a) Dehydrohalogenation
Explanation: Dehydrohalogenation is the elimination reaction where an alkyl halide loses a hydrogen atom and a halogen atom to form an alkene.
Q.34: Which of the following does not undergo nucleophilic substitution easily?
(a) Chlorobenzene
(b) Ethyl chloride
(c) Benzyl chloride
(d) Propyl chloride
Answer: (a) Chlorobenzene
Explanation: Chlorobenzene does not undergo nucleophilic substitution easily due to the partial double bond character of the C-Cl bond resulting from resonance.
Q.35: Which of the following is a Grignard reagent?
(a) CH₃CH₂MgBr
(b) CH₃CH₂OH
(c) CH₃CH₂Cl
(d) CH₃CH₂ONa
Answer: (a) CH₃CH₂MgBr
Explanation: A Grignard reagent is an organomagnesium halide, such as CH₃CH₂MgBr, used in various organic synthesis reactions.
Q.36: Which of the following is used as a solvent in dry cleaning?
(a) Carbon tetrachloride
(b) Ethanol
(c) Acetone
(d) Benzene
Answer: (a) Carbon tetrachloride
Explanation: Carbon tetrachloride (CCl₄) is used as a solvent in dry cleaning due to its non-flammability and ability to dissolve oils and fats.
Q.37: Which of the following does not form a Grignard reagent?
(a) Fluorobenzene
(b) Chlorobenzene
(c) Bromobenzene
(d) Iodobenzene
Answer: (a) Fluorobenzene
Explanation: Fluorobenzene does not form a Grignard reagent due to the strong C-F bond, which is difficult to break.
Q.38: Which of the following compounds is most reactive towards nucleophilic substitution?
(a) Methyl iodide
(b) Methyl bromide
(c) Methyl chloride
(d) Methyl fluoride
Answer: (a) Methyl iodide
Explanation: Methyl iodide is most reactive towards nucleophilic substitution due to the weak C-I bond, which is easily broken.
Q.39: Which of the following can be used as a reagent to convert an alcohol to a chloroalkane?
(a) SOCl₂
(b) HCl
(c) PCl₅
(d) All of the above
Answer: (d) All of the above
Explanation: All the listed reagents (SOCl₂, HCl, PCl₅) can be used to convert an alcohol to a chloroalkane by replacing the hydroxyl group with a chlorine atom.
Q.40: The major product of the reaction between benzene and methyl chloride in the presence of anhydrous AlCl₃ is:
(a) Toluene
(b) Chlorobenzene
(c) Benzyl chloride
(d) Xylene
Answer: (a) Toluene
Explanation: The reaction is an example of Friedel-Crafts alkylation, where benzene reacts with methyl chloride to form toluene.
Q.41: Which of the following halides can be prepared by the reaction of an alcohol with HCl and ZnCl₂?
(a) Methyl chloride
(b) Ethyl bromide
(c) Propyl iodide
(d) Benzyl chloride
Answer: (a) Methyl chloride
Explanation: The reaction of an alcohol with HCl and ZnCl₂, known as the Lucas test, is used to prepare alkyl chlorides, such as methyl chloride.
Q.42: Which of the following statements is incorrect about haloalkanes?
(a) They are generally soluble in water.
(b) They have higher boiling points than alkanes of similar molecular weight.
(c) They can undergo nucleophilic substitution reactions.
(d) They can undergo elimination reactions.
Answer: (a) They are generally soluble in water.
Explanation: Haloalkanes are generally insoluble in water due to their inability to form hydrogen bonds with water molecules.
Q.43: Which of the following is used as an insecticide?
(a) DDT
(b) Methanol
(c) Ethanol
(d) Benzene
Answer: (a) DDT
Explanation: DDT (Dichlorodiphenyltrichloroethane) is used as an insecticide to control mosquito-borne diseases and agricultural pests.
Q.44: Which of the following halides is least reactive towards nucleophilic substitution?
(a) RF
(b) RCl
(c) RBr
(d) RI
Answer: (a) RF
Explanation: Fluoroalkanes (RF) are least reactive towards nucleophilic substitution due to the strong C-F bond.
Q.45: Which of the following compounds is most reactive towards an SN2 reaction?
(a) Methyl chloride
(b) Ethyl chloride
(c) Isopropyl chloride
(d) tert-Butyl chloride
Answer: (a) Methyl chloride
Explanation: Methyl chloride is most reactive towards an SN2 reaction due to the minimal steric hindrance around the electrophilic carbon.
Q.46: Which of the following halides is used in the preparation of freons?
(a) Methyl chloride
(b) Ethyl bromide
(c) Vinyl chloride
(d) Chloroform
Answer: (a) Methyl chloride
Explanation: Methyl chloride (CH₃Cl) is used in the preparation of freons, which are chlorofluorocarbons used as refrigerants.
Q.47: The major product of the reaction between benzene and bromine in the presence of iron(III) bromide is:
(a) Bromobenzene
(b) Benzyl bromide
(c) Dibromobenzene
(d) Benzene hexabromide
Answer: (a) Bromobenzene
Explanation: The reaction is an example of electrophilic aromatic substitution, where benzene reacts with bromine in the presence of FeBr₃ to form bromobenzene.
Q.48: Which of the following is used in the manufacture of dyes and drugs?
(a) Chlorobenzene
(b) Benzene
(c) Ethylene
(d) Toluene
Answer: (a) Chlorobenzene
Explanation: Chlorobenzene is used as a solvent and intermediate in the manufacture of dyes and drugs.
Q.49: Which of the following is used as a fire extinguishing agent?
(a) Carbon tetrachloride
(b) Methanol
(c) Ethanol
(d) Benzene
Answer: (a) Carbon tetrachloride
Explanation: Carbon tetrachloride (CCl₄) is used as a fire extinguishing agent due to its ability to inhibit the combustion process.
Q.50: Which of the following is used in the production of PVC?
(a) Vinyl chloride
(b) Ethylene
(c) Propylene
(d) Styrene
Answer: (a) Vinyl chloride
Explanation: Polyvinyl chloride (PVC) is produced by the polymerization of vinyl chloride monomer.
Q.51: Which of the following can undergo nucleophilic aromatic substitution?
(a) Nitrobenzene
(b) Chlorobenzene
(c) Toluene
(d) Benzene
Answer: (a) Nitrobenzene
Explanation: Nitrobenzene can undergo nucleophilic aromatic substitution because the nitro group is an electron-withdrawing group that activates the benzene ring for nucleophilic attack.
Q.52: The IUPAC name of (CH₃)₃CCl is:
(a) 1-Chloro-2,2-dimethylpropane
(b) 2-Chloro-2-methylpropane
(c) tert-Butyl chloride
(d) 2-Chlorobutane
Answer: (b) 2-Chloro-2-methylpropane
Explanation: The IUPAC name of (CH₃)₃CCl is 2-Chloro-2-methylpropane, which indicates the presence of a chlorine atom attached to the second carbon of a 2-methylpropane.
Q.53: Which of the following is a primary alkyl halide?
(a) 1-Chlorobutane
(b) 2-Chlorobutane
(c) tert-Butyl chloride
(d) sec-Butyl chloride
Answer: (a) 1-Chlorobutane
Explanation: 1-Chlorobutane is a primary alkyl halide as the chlorine atom is attached to a primary carbon atom.
Q.54: Which of the following is not a chlorofluorocarbon (CFC)?
(a) Freon-12
(b) Freon-22
(c) CFCl₃
(d) CH₃Cl
Answer: (d) CH₃Cl
Explanation: CH₃Cl (methyl chloride) is not a chlorofluorocarbon as it contains hydrogen atoms in addition to chlorine and carbon atoms.
Q.55: Which of the following statements about haloalkanes is true?
(a) They are generally hydrophilic.
(b) They can be used as anesthetics.
(c) They have lower boiling points than alkanes of similar molecular weight.
(d) They are always gases at room temperature.
Answer: (b) They can be used as anesthetics.
Explanation: Some haloalkanes, such as chloroform and halothane, have been used as anesthetics.
Q.56: Which of the following halides is used as a refrigerant?
(a) Freon-12
(b) Ethyl bromide
(c) Vinyl chloride
(d) Benzyl chloride
Answer: (a) Freon-12
Explanation: Freon-12 (CCl₂F₂) is used as a refrigerant in air conditioning and refrigeration systems.
Q.57: Which of the following compounds is used as an anesthetic in surgery?
(a) Chloroform
(b) Methanol
(c) Ethanol
(d) Benzene
Answer: (a) Chloroform
Explanation: Chloroform (CHCl₃) was historically used as an anesthetic in surgery due to its ability to induce unconsciousness.
Q.58: Which of the following can be used to prepare a Grignard reagent?
(a) Ethyl chloride
(b) Ethyl alcohol
(c) Ethyl acetate
(d) Ethylamine
Answer: (a) Ethyl chloride
Explanation: Ethyl chloride can react with magnesium in dry ether to form a Grignard reagent, ethylmagnesium chloride.
Q.59: Which of the following is a secondary alkyl halide?
(a) Isopropyl chloride
(b) Methyl chloride
(c) Ethyl chloride
(d) n-Propyl chloride
Answer: (a) Isopropyl chloride
Explanation: Isopropyl chloride is a secondary alkyl halide as the chlorine atom is attached to a secondary carbon atom.
Q.60: The major product of the reaction between benzene and methyl chloride in the presence of anhydrous AlCl₃ is:
(a) Toluene
(b) Chlorobenzene
(c) Benzyl chloride
(d) Xylene
Answer: (a) Toluene
Explanation: The reaction is an example of Friedel-Crafts alkylation, where benzene reacts with methyl chloride to form toluene.
