123 + Interview Questions in Haloalkanes And Haloarenes in Chemistry

101.	Which of the following is not a use of carbon tetrachloride?(a) Manufacturing of refrigerants(b) Manufacturing of pharmaceuticals(c) Degreasing agent(d) InsecticideThis question was addressed to me in my homework.This intriguing question originated from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct choice is (d) Insecticide The best I can explain: CCL4 is PRODUCED in large QUANTITIES for use in the making of refrigerants and propellants for aerosol CANS. It is also used as feedstock in pharmaceutical manufacturing and synthesis of chlorofluorocarbons.

Discussion

102.	Which is the metal involved in Wurtz-Fittig reaction?(a) Iron(b) Magnesium(c) Aluminium(d) SodiumI have been asked this question in semester exam.My enquiry is from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT option is (d) Sodium To explain: When an ARYL HALIDE and alkyl halide and TOGETHER treated with sodium metal in DRY ether, an alkylarene is formed. This is called Wurtz-Fittig reaction.

Discussion

103.	The C-Cl bond length in chlorobenzene is less than the C-Cl bond length in chloromethane because of the ________(a) resonance effect in haloarenes(b) difference in hybridisation of carbonin C-Cl bond(c) instability of phenyl cation(d) possible repulsion between nucleophile and chlorobenzeneI got this question in homework.I want to ask this question from Haloalkanes & Haloarenes topic in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right choice is (b) difference in HYBRIDISATION of carbonin C-Cl BOND To EXPLAIN I would SAY: In chlorobenzene, the C of C-Cl bond is sp^2 hybridised, whereas the C of C-Cl bond in CHLOROMETHANE is sp^3 hybridised. Thus, there is more s character in the carbon of the C-Cl bond in chlorobenzene and as a result holds the electron pair of C-Cl bond more tightly.

Discussion

104.	Which of the following is the suitable medium for preparing Grignard reagents?(a) Dry acetone(b) Dry ether(c) Concentrated HCl(d) Alcoholic KOHI have been asked this question in unit test.Query is from Haloalkanes & Haloarenes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct ANSWER is (b) DRY ether Easy explanation: When haloalkanes react with MAGNESIUM metal in dry ether, special organo-metallic compounds CALLED Grignard REAGENTS are formed.

Discussion

105.	Iodomethane reacts faster than bromomethane in SN2 reaction with OH^–?(a) True(b) FalseI had been asked this question during a job interview.The doubt is from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct choice is (a) True For explanation I would say: IODINE is a better LEAVING GROUP because of its large SIZE and will be released at a faster rate in the presence of a nucleophile.

Discussion

106.	The reaction between chloroethane and potassium hydroxide is a _______ order reaction.(a) zero(b) first(c) second(d) thirdI have been asked this question during an online exam.This intriguing question comes from Haloalkanes & Haloarenes in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» RIGHT option is (c) second To explain: This nucleophilic reaction follows SN2 MECHANISM and its rate depends on the concentration of both CHLOROETHANE and hydroxide IONS. Hence, it is a bimolecular reaction.

Discussion

107.	What is the by-product formed along with the haloarene at the end of Sandmeyer’s reaction?(a) H2O(b) HCl(c) NO2(d) N2The question was posed to me during an interview.My doubt stems from Preparation of Haloarenes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (d) N2 The best I can explain: When a diazonium SALT SOLUTION is treated with cuprous chloride/bromide, it gives an ARYL halide ALONG with nitrogen as. This is called Sandmeyer’s reaction.

Discussion

108.	The prefix bis is used when two complex substituents are present on the same of different C atoms on a hydrocarbon.(a) True(b) FalseI have been asked this question at a job interview.The doubt is from Haloalkanes Nomenclature in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT choice is (a) True For EXPLANATION I would say: The prefix bis is used instead of di for COMPLEX SUBSTITUENTS in hydrocarbons before the name of the substituent which is enclosed in brackets.

Discussion

109.	Freon 12 is manufactured from the Swarts reaction of which compound?(a) Dichloromethane(b) Trichloromethane(c) Tetrachloromethane(d) DichlorodifluoromethaneThis question was posed to me in an online interview.I'd like to ask this question from Haloalkanes & Haloarenes in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The CORRECT option is (C) Tetrachloromethane The best I can EXPLAIN: Freon 12 (CCl2F2) is OBTAINED by heating CCL4 with antimony fluoride in the presence of antimony pentachloride by Swarts reaction.

Discussion

110.	Which of the following compounds is most easily converted to a phenol when heated with aqueous NaOH solution?(a) Chlorobenzene(b) 4-Chloronitrobenzene(c) 2,4-Dinitrochlorobenzene(d) 2,4,6-TrinitrochlorobenzeneThis question was addressed to me in a job interview.The doubt is from Haloalkanes & Haloarenes topic in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct answer is (d) 2,4,6-Trinitrochlorobenzene To elaborate: The presence of ELECTRON withdrawing GROUPS like NO2 at ortho and para POSITIONS with RESPECT to the halogen, increases the reactivity of the haloarene. Chlorobenzene has no such group and converts to phenol at the highest temperature and pressure.

Discussion

111.	What will be the effect on the plane of plane polarised light when it passes through a solution of dlbutan-2-ol?(a) Clockwise rotation(b) Anti-clockwise rotation(c) Zero rotation(d) 180° rotationI have been asked this question during an online exam.Question is from Haloalkanes & Haloarenes in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT answer is (c) Zero rotation To elaborate: dlbutan-2-ol represents a MIXTURE of dbutan-2-ol (dextro) and lbutan-2-ol (laevo), and is called a RACEMIC mixture. There optical rotation due to ONE isomer will cancel the rotation due to the other and will have no effect on the polarised light passed through it.

Discussion

112.	Tertiary alkyl halides show higher reactivity towards bimolecular nucleophilic substitution than secondary alkyl halides.(a) True(b) FalseThe question was posed to me during a job interview.The origin of the question is Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right answer is (B) False To explain: Tertiary alkyl halides have more alkyl groups PRESENT around the carbon linked to the halogen, which CAUSES steric hinderance of the nucleophile and hence the REACTIVITY towards SN2 reactions reduces significantly.

Discussion

113.	Which of the following has the highest density?(a) CH3Cl(b) CH2Cl2(c) CHCl3(d) CCl4This question was addressed to me by my school teacher while I was bunking the class.This interesting question is from Haloarenes Physical Properties in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct choice is (d) CCl4 The best I can explain: The DENSITY of haloalkanes increases with the number of HALOGEN atoms PRESENT in because of increase in MOLECULAR WEIGHT.

Discussion

114.	When ethanol reacts with PCl5, it gives three products which include chloroethane and hydrochloric acid. What is the third product?(a) Phosphorus acid(b) Phosphoric acid(c) Phosphorus trichloride(d) Phosphoryl chlorideThis question was addressed to me during a job interview.The query is from Methods of Preparation of Haloalkanes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right OPTION is (d) Phosphoryl chloride The best explanation: The reaction of CH3CH2OH with PCL5 yields CH3CH2Cl, POCL3 (phosphoryl acid) and HCl. This is a method of preparation of CHLOROALKANES from alcohols.

Discussion

115.	The correct naming of the compound CH≡C-CH=CH-CH3 is __________(a) Pent-3-en-1-yne(b) Pent-2-en-4-yne(c) Pent-3-ene-1-yne(d) Pent-2-ene-4-yneI have been asked this question during a job interview.This interesting question is from Haloalkanes Nomenclature topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct option is (a) Pent-3-en-1-yne Easiest explanation: The lower SET of LOCANTS is 1, 3 rather than 2, 4. This compound is named as a derivative of alkyne and not alkenes. Also, the TERMINAL ‘e’ in ene is dropped because it comes before ‘y’ of yne.

Discussion

116.	How many carbon atoms does Isobutyl chloride have in its parent carbon chain?(a) 2(b) 3(c) 4(d) 5I got this question in an international level competition.Question is from Haloalkanes Nomenclature topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right ANSWER is (b) 3 To explain I would say: The IUPAC NAME of Isobutyl chloride is 1-Chloro-2-methylpropane, which means the PARENT chain CONSISTS of 3 carbon atoms with an alkyl group at C-2 and a halogen at C-1.

Discussion

117.	Identify the nucleophile that gives a primary amine and hydrogen bromide on reaction with bromoethane.(a) NH2(b) NH3(c) H2O(d) HThe question was posed to me during an online interview.My question is based upon Haloalkanes & Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct CHOICE is (b) NH3 To elaborate: AMMONIA reacts with alkyl halides to undergo NUCLEOPHILIC substitution and form amine and a mineral acid.

Discussion

118.	Which of the followings reagents forms an isonitrile when reacted with an alkyl halide?(a) KCN(b) AgCN(c) KNO2(d) AgNO2I have been asked this question in an interview for job.The doubt is from Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The CORRECT option is (b) AgCN Explanation: AgCN has a LONE pair of electrons on the N ATOM and ATTACKS from the N side to FORMS a compound of the type RNC, where R is the alkyl group.

Discussion

119.	The reaction that takes place when an electron rich species stronger than the halide approaches the partially positive carbon atom of a haloalkane and forms a new bond with the carbon atom and in the process displacing the halogen is called a ________ reaction.(a) displacement(b) electrophilic substitution(c) nucleophilic substitution(d) eliminationThe question was posed to me in unit test.This intriguing question originated from Haloalkanes & Haloarenes in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct answer is (c) NUCLEOPHILIC substitution To EXPLAIN: Nucleophiles are electron rich species and when a stronger nucleophile REPLACES an already EXISTING one is called a nucleophilic substitution REACTION.

Discussion

120.	If chloromethane has a boiling point of 250K, what will be the probable boiling point of methane?(a) 110K(b) 250K(c) 275K(d) 315KI got this question in an internship interview.My question is based upon Haloarenes Physical Properties in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct option is (a) 110K Easiest explanation: Haloalkanes are POLAR in NATURE and have higher intermolecular forces of attraction in TERMS of dipole-dipole and van der Waal forces. Hence, the boiling POINTS of haloalkanes are higher than their respective HYDROCARBONS.

Discussion

121.	What is the value of diploe moment of p-Dichlorobenzene?(a) 0(b) 1(c) >1(d)
Answer» RIGHT option is (a) 0 To explain I WOULD say: The para isomer of dichlorobenzene is SYMMETRICAL and the two equal dipoles on opposite sides CANCEL and RESULT in zero dipole moment.

Discussion

122.	The carbon-halogen bond of an alkyl halide is polarised due to the _________(a) higher electronegativity of halogen atom than carbon(b) higher electronegativity of carbon than halogen atom(c) partial positive charge on halogen atom and a partial negative charge on carbon(d) tendency of halogen atom to donate electronsThe question was asked at a job interview.The query is from Nature of C-X Bond in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT answer is (a) higher electronegativity of halogen atom than carbon The best explanation: Polarity occurs between two entities when there is a DIFFERENCE in the magnitude and signs of CHARGES between the two entities. In this case, the halogen is more negatively CHARGED than the carbon, and hence it is POLARISED.

Discussion

123.	What is the IUPAC name of the following compound?(a) 2-Propylprop-1-ene(b) 2,3-Dimethylbut-1-ene(c) 2,4-Dimethylbut-1-ene(d) 1,3-Dimethylbut-2-eneThe question was asked during an internship interview.My question is from Haloalkanes Nomenclature in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct option is (B) 2,3-Dimethylbut-1-ene The best I can explain: The parent carbon chain must INCLUDE the double BOND, so there are 4 C atoms including the C-C double bond and the double bond is present at C-1 with TWO METHYL groups at positions 2 and 3.

Discussion

Explore topic-wise InterviewSolutions in .

Which is the metal involved in Wurtz-Fittig reaction?(a) Iron(b) Magnesium(c) Aluminium(d) SodiumI have been asked this question in semester exam.My enquiry is from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12

Which of the following is the suitable medium for preparing Grignard reagents?(a) Dry acetone(b) Dry ether(c) Concentrated HCl(d) Alcoholic KOHI have been asked this question in unit test.Query is from Haloalkanes & Haloarenes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12

Iodomethane reacts faster than bromomethane in SN2 reaction with OH^–?(a) True(b) FalseI had been asked this question during a job interview.The doubt is from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12

What is the by-product formed along with the haloarene at the end of Sandmeyer’s reaction?(a) H2O(b) HCl(c) NO2(d) N2The question was posed to me during an interview.My doubt stems from Preparation of Haloarenes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12

The prefix bis is used when two complex substituents are present on the same of different C atoms on a hydrocarbon.(a) True(b) FalseI have been asked this question at a job interview.The doubt is from Haloalkanes Nomenclature in division Haloalkanes and Haloarenes of Chemistry – Class 12

Which of the following has the highest density?(a) CH3Cl(b) CH2Cl2(c) CHCl3(d) CCl4This question was addressed to me by my school teacher while I was bunking the class.This interesting question is from Haloarenes Physical Properties in section Haloalkanes and Haloarenes of Chemistry – Class 12

How many carbon atoms does Isobutyl chloride have in its parent carbon chain?(a) 2(b) 3(c) 4(d) 5I got this question in an international level competition.Question is from Haloalkanes Nomenclature topic in section Haloalkanes and Haloarenes of Chemistry – Class 12

Identify the nucleophile that gives a primary amine and hydrogen bromide on reaction with bromoethane.(a) NH2(b) NH3(c) H2O(d) HThe question was posed to me during an online interview.My question is based upon Haloalkanes & Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12

Which of the followings reagents forms an isonitrile when reacted with an alkyl halide?(a) KCN(b) AgCN(c) KNO2(d) AgNO2I have been asked this question in an interview for job.The doubt is from Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12

If chloromethane has a boiling point of 250K, what will be the probable boiling point of methane?(a) 110K(b) 250K(c) 275K(d) 315KI got this question in an internship interview.My question is based upon Haloarenes Physical Properties in portion Haloalkanes and Haloarenes of Chemistry – Class 12

What is the value of diploe moment of p-Dichlorobenzene?(a) 0(b) 1(c) >1(d)