123 + Interview Questions in Haloalkanes And Haloarenes in Chemistry

51.	Calculate the dipole moment of m-Dichlorobenzene if the dipole moments of C-Cl bondsare 1.72D.(a) 0(b) 1.72D(c) 2.54D(d) 2.98DThe question was asked in an internship interview.My question is based upon Haloarenes Physical Properties topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» RIGHT option is (b) 1.72D To elaborate: The angle between the two halogen atoms in meta isomer is 120° and let the DIPOLE moments of C-Cl bonds be d=1.72D and let d’ be the dipole moment of the compound. So, by law of PARALLELOGRAM of FORCES, \(\Rightarrow \,d’ = \sqrt{d^2 + d^2 + 2d^2.cos(120°)}\) \(\Rightarrow \,d’ = \sqrt{1.72^2 + 1.72^2 – (2 \,X\, 0.5 \,x\, 1.72^2)}\) \(\Rightarrow \,d’ = \sqrt{1.72^2}\) \(\Rightarrow \,d’ = 1.72D\)

Discussion

52.	The boiling points of isomeric alkyl halides _______ with increase in branching.(a) increase(b) decrease(c) remains same(d) cannot be determinedI have been asked this question in an online quiz.Asked question is from Haloarenes Physical Properties in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (b) decrease Best explanation: The branching of compounds MAKES it more compact and REDUCES the surface area, which in TURN van der WAALS ATTRACTION forces and thus, decrease the boiling point.

Discussion

53.	The Finkelstein reaction can be used to prepare alkyl fluorides.(a) True(b) FalseI have been asked this question during an online interview.I need to ask this question from Methods of Preparation of Haloalkanes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct answer is (b) False Explanation: The REAGENT in Finkelstein reaction is STRICTLY sodium IODIDE which reacts with either alkyl bromides or CHLORIDES to exchange the iodine with the other halogen group to form alkyl iodides.

Discussion

54.	Identify the missing compound Y.(a) NaBr(b) HBr(c) HCl(d) Cu2Br2The question was asked at a job interview.Query is from Preparation of Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct choice is (b) HBr To explain: This is the diazotisation reaction where an AROMATIC amine in aqueous mineral acid (HBr) is treated with NaNO2 at cold TEMPERATURE to FORM respective DIAZONIUM SALTS.

Discussion

55.	What happens when a solution of benzene diazonium bromide and an aqueous solution potassium iodide are shaken together?(a) Iodobenzene is formed(b) Bromobenzene is formed(c) A dihaloarene is formed(d) No reactionThe question was asked in an internship interview.This interesting question is from Preparation of Haloarenes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct ANSWER is (a) Iodobenzene is formed The best I can explain: SINCE iodine is more reactive, the replacement of diazonium GROUP to form iodobenzene does not require the presence of a cuprous HALIDE and is done simply by SHAKING the diazonium salt with KI.

Discussion

56.	When (-)-2-bromooctane reacts with potassium hydroxide over an SN2 mechanism, what will be the product formed?(a) (-)-octan-1-ol(b) (+)-octan-1-ol(c) (-)-octan-2-ol(d) (+)-octan-2-olI had been asked this question during an interview.This interesting question is from Haloalkanes & Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct choice is (d) (+)-octan-2-ol Explanation: The OH NUCLEOPHILE attaches itself OPPOSITE to where the halide was PRESENT but one the same carbon. This results in an inversion of configuration and hence changes in the direction in which the plane of polarised LIGHT rotates.

Discussion

57.	What is the correct order of reactivity of haloalkanes towards β-elimination reactions?(a) 1°>2°>3°(b) 3°>2°>1°(c) 1°>3°>2°(d) 3°>1°>2°I got this question in homework.Asked question is from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct choice is (B) 3°>2°>1° Easiest explanation: The HALOALKANES which will FORM more stable (highly substituted) alkenes are the ones that will react the fastest. Since TERTIARY alkyl HALIDES will form the most stable alkenes, they are the most reactive.

Discussion

58.	Which of the following are the most suitable conditions for electrophilic substitution of arenes?(a) UV light and heat(b) Cold and dark(c) 40^oC temperature and dark(d) Room temperature and sunlightThe question was asked during an online interview.My doubt stems from Preparation of Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct answer is (c) 40^oC temperature and DARK To ELABORATE: This reaction is CARRIED out in the dark at ordinary temperatures (310-320K) in the presence of a Lewis acid CATALYST.

Discussion

59.	When propene reacts with HBr, two products are formed out of which one is predominates the other. Identify the minor product.(a) 1-Bromopropane(b) 2-Bromopropane(c) 1-Bromobutane(d) 2-BromobutaneThe question was asked in an online quiz.Question is from Methods of Preparation of Haloalkanes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right answer is (a) 1-Bromopropane To explain I WOULD say: According to Markovnikov’s rule, the negative part of the REAGENT (Br) attaches itself to the C ATOM with lesser number of hydrogen ATOMS. Hence, the Br attaches majorly to the second C atom of propane and forms 2-Bromopropane as the major product.

Discussion

60.	How many monohaloalkane isomers can be formed on the free radical bromination of (CH3)2CHCH2CH3?(a) 2(b) 3(c) 4(d) 5This question was addressed to me in an online quiz.This intriguing question comes from Methods of Preparation of Haloalkanes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct choice is (C) 4 Easy explanation: There are four DIFFERENT types of hydrogen atoms that can be REPLACED to give the following four isomers; (CH3)2CHCH2CH2Br, (CH3)2CHCH(Br)CH3, (CH3)2C(Br)CH2CH3 and CH3CH(CH2BR)CH2CH3.

Discussion

61.	What is the catalyst in the reaction of a primary alcohol with HCl to obtain a chloroalkane?(a) anhydrous ZnCl2(b) concentrated H2SO4(c) red phosphorous(d) pyridineThe question was asked in an interview for job.My query is from Methods of Preparation of Haloalkanes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT CHOICE is (a) anhydrous ZNCL2 The best explanation: The presence of anhydrous ZnCl2 is to be break the C-O bond in ALCOHOLS. ZnCl2 is a Lewis acid and reacts with the oxygen of the alcohol GROUP.

Discussion

62.	Which of the following is not the correct IUPAC name for the compound shown?(a) 1-Chloro-3-methylbenzene(b) 3-Chloromethylbenzene(c) 3-Chlorotoluene(d) m-ChlorotolueneI have been asked this question in class test.I need to ask this question from Haloalkanes Nomenclature in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» RIGHT CHOICE is (d) m-Chlorotoluene Explanation: All the names GIVEN are appropriate for the shown compound, but m-Chlorotoluene is the common NAME and not the IUPAC name.

Discussion

63.	Chloroform was previously used as a general anaesthetic in surgery.(a) True(b) FalseThe question was asked in an internship interview.The above asked question is from Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (a) True To explain I would SAY: It was STOP being used as an anaesthetic due to its TOXICITY and HARMFUL effects on the human body. It was replaced by safer options LIKE ether.

Discussion

64.	A haloalkane is known to have an SN2 reaction rate 30 times faster than that of ethyl bromide. Identify the haloalkane.(a) Methyl bromide(b) Isopropyl bromide(c) tert-Butyl bromide(d) neo-Pentyl bromideI had been asked this question at a job interview.Asked question is from Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct OPTION is (a) Methyl bromide Explanation: The presence of bulky groups around the C atom has an inhibiting effect on the rate of SN2 reaction. SINCE methyl bromide has only three H atoms around the C, it will have a HIGHER rate than ETHYL bromide.

Discussion

65.	If the compound shown has a boiling point of 346K, predict the boiling point of n-Butyl bromide?(a) 300K(b) 325K(c) 350K(d) 375KThis question was addressed to me in quiz.The origin of the question is Haloarenes Physical Properties topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (d) 375K To explain I would say: The COMPOUND SHOWN is a highly branched isomer of n-Butyl bromide, i.e., tert-Butyl bromide. The n-Butyl bromide structure has no branches and therefore has a SIGNIFICANTLY HIGHER boiling point than tert-Butyl bromide.

Discussion

66.	What is the correct order of reactivity of alcohols with a given haloacid?(a) 1° > 2° > 3°(b) 3° > 2° > 1°(c) 1° > 3° > 2°(d) 2° > 1° > 3°This question was posed to me during an interview.This interesting question is from Methods of Preparation of Haloalkanes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct choice is (b) 3° > 2° > 1° For EXPLANATION: When more number of electron DONATING groups are bonded to the C atom attached to the OH group, the polarity of C-OH bond increases. Thus, the reactivity of the ALCOHOL increases.

Discussion

67.	In which of the following cases will the compound be a tertiary (3°) halogen compound? (X=halogen atom)(a) R’=R”=H(b) R’=CH3, R”=H(c) R’=H, R”=CH3(d) R’=R”=CH3The question was asked in examination.The query is from Haloalkanes Classification in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right OPTION is (d) R’=R”=CH3 The best I can EXPLAIN: When R and R’ both are CH3 groups, then the carbon ATOM bonded to the halogen will have three alkyl groups attached to it including the benzene RING.

Discussion

68.	Which of the following is a vinylic halide?(a) CH2=CHCHCl2(b) CH3CHClCH3(c) (CH3)2C=CHCH2Cl(d) CH3CH=CClCH2CH3I had been asked this question during an internship interview.My doubt stems from Haloalkanes Classification topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct option is (d) CH3CH=CClCH2CH3 Easy EXPLANATION: In CH3CH=CClCH2CH3, the Cl is bonded DIRECTLY to the C atom of a C-C DOUBLE bond, and hence it is a vinylic halide. CH3CHClCH3 is an alkyl halide whereas CH2=CHCHCl2 and (CH3)2C=CHCH2Cl are allylic halides.

Discussion

69.	If X and Y are the carbon-halogen bond enthalpies in chloroethane and bromoethane respectively, what is the relationship between X and Y?(a) X > Y(b) X < Y(c) X = Y(d) X + Y = 0I have been asked this question in semester exam.This is a very interesting question from Nature of C-X Bond in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT option is (b) X < Y The best I can explain: Since the C-F bond length will be shorter than the C-Cl bond length DUE to the smaller size of F atom, it will require more energy to break the C-F bond, HENCE the enthalpy value of C-Cl bond will be LOWER than that of C-F bond.

Discussion

70.	Which of the following categories does the compound shown belong to?(a) Primary haloalkane(b) Secondary haloalkane(c) Tertiary haloalkane(d) HaloareneI had been asked this question during an interview.Question is from Haloalkanes Classification topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right answer is (b) Secondary haloalkane Easiest explanation: The compound shown is cyclohexyl iodide, in which the halogen atom is bonded to an ALKYL GROUP that is alicyclic in nature. Since there are effectively two alkyl groups ATTACHED to the CARBON bonded to the halogen atom, it is CLASSIFIED as secondary or 2° cyclo alkyl halide.

Discussion

71.	A monohaloarene is an example of a/an __________(a) aliphatic halogen compound(b) aromatic halogen compound(c) alkyl halide(d) side chain substituted aryl halideI had been asked this question in quiz.My question comes from Haloalkanes Classification in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right option is (B) aromatic halogen compound Easy explanation: A monohaloarene is a compound in which the halogen is directly attached to the benzene RING. Side CHAIN substituted aryl halides are ALSO aromatic halogen COMPOUNDS with the halogen not directly attached to the benzene ring.

Discussion

72.	Which of the following is not a use of methylene chloride?(a) Paint removal(b) Propellant in aerosols(c) Metal cleaning(d) AntisepticThe question was posed to me in my homework.I'm obligated to ask this question of Haloalkanes & Haloarenes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct CHOICE is (d) Antiseptic Easiest explanation: Methylene chloride can harm the HUMAN CENTRAL nervous system and application on the skin MAY result in intense BURNING and redness.

Discussion

73.	Which of the following is not a characteristic of CHClF2?(a) Non-toxic(b) Non-flammable(c) Non-corrosive(d) Non-liquefiableThis question was posed to me in examination.I'm obligated to ask this question of Haloalkanes & Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right ANSWER is (d) Non-liquefiable The explanation: CHClF2 is a freon refrigerant ALSO known as R-22. It is EXTREMELY STABLE, unreactive, non-toxic, non-corrosive and an EASILY liquefiable gas.

Discussion

74.	2-Chloronitrobenzene is more reactive than chlorobenzene.(a) True(b) FalseThe question was posed to me in an international level competition.My question is taken from Haloalkanes & Haloarenes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct option is (b) False The explanation: Although NO2 is an electron WITHDRAWING group, it is present at META position with respect to chlorine in 2-Chloronitrobenzene and has no EFFECT on the reactivity of the haloarene. This is because none of the resonating STRUCTURES of m-nitrobenzene bear the negative charge on the carbon ATOM bearing the nitro group and as a result the presence of NO2 at meta position does not stabilize the negative charge.

Discussion

75.	Which of the following compounds does not have a stereocenter?(a) Propan-2-ol(b) Butan-2-ol(c) 2-Bromo-1-chlorobutane(d) 2-BromopentaneI have been asked this question during a job interview.My question is taken from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right option is (a) Propan-2-ol For EXPLANATION I would SAY: A stereocenter is an asymmetric carbon that has FOUR different GROUPS attached to it. Propan-2-ol has two METHYL groups attached to the carbon.

Discussion

76.	The compound 2,2-Dichlorobutane is a geminal dihalide.(a) True(b) FalseI had been asked this question during a job interview.I'm obligated to ask this question of Haloalkanes Nomenclature topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT option is (a) True Easy explanation: The COMPOUND is dihaloalkane with 2 chlorine atoms one the same carbon atom, HENCE it is a GEM dihalide.

Discussion

77.	Carbon tetrarchloride may indirectly cause skin cancer.(a) True(b) FalseThis question was addressed to me in final exam.My question is taken from Haloalkanes & Haloarenes topic in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (a) True Easiest explanation: When CCl4 is released into the ATMOSPHERE, it causes the DEPLETION of the ozone layer, which increases exposure to UV RAYS leading to SKIN cancer, eye diseases and disorders.

Discussion

78.	Which is the largest halogen atom?(a) Bromine(b) Chlorine(c) Fluorine(d) IodineThis question was addressed to me during an interview.I would like to ask this question from Nature of C-X Bond topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right CHOICE is (d) IODINE Best EXPLANATION: Iodine lies below bromine, chlorine and fluorine in the halogen group and hence has the largest ATOMIC size.

Discussion

79.	A chiral compound with an ‘X’ group attached to the stereocenter has been replaced by a ‘Y’ group. The product obtained rotates the plane of polarised light in the direction opposite to that of the original compound. Name the process that has taken place.(a) Inversion(b) Retention(c) Racemisation(d) Inversion or retentionThis question was posed to me in an international level competition.Origin of the question is Haloalkanes & Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (d) Inversion or retention Explanation: Since the PRODUCT ROTATES the PLANE of polarised LIGHT in some direction, it cannot be racemic. The product formed is a completely new compound from the original one and may have different or same OPTICAL behaviour as compared to the original compound.

Discussion

80.	Which of the following statements is correct regarding unimolecular nucleophilic substitution reactions?(a) It takes place in three steps.(b) The rate of the reaction depends on the concentration of all the reactants.(c) The first step is the slowest and determines the rate of reaction.(d) None of the steps are reversible.The question was posed to me during an interview.Origin of the question is Haloalkanes & Haloarenes in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right CHOICE is (c) The first step is the slowest and DETERMINES the rate of reaction. Explanation: SN1 reactions FOLLOW first order kinetics and take place in two STEPS, of which the first ONE is the slowest, rate determining and reversible step.

Discussion

81.	Haloalkanes are more soluble in water than in alcohols.(a) True(b) FalseI got this question in an interview.Question is from Haloarenes Physical Properties in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct ANSWER is (b) False The explanation is: Haloalkanes are very slightly soluble in WATER due to the strong hydrogen bonds between water molecules. However, they dissolve much more easily in organic solvents as the strength of new forces is SIMILAR to that of existing INTERMOLECULAR attractions.

Discussion

82.	The compound C6H5F is an example of a ________ halide.(a) allylic(b) benzylic(c) vinylic(d) arylThe question was asked in exam.My question is from Haloalkanes Classification in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The CORRECT choice is (d) aryl To explain: In C6H5F, the F atom is directly attached to the sp^2 hybridised carbon atom of an AROMATIC RING, i.e., benzene.

Discussion

83.	Iodoalkanes can be obtained by heating alcohols with potassium iodide in __________(a) hypophosphrus acid(b) phosphorus acid(c) phosphoric acid(d) hypophosphoric acidI had been asked this question during an online interview.I'd like to ask this question from Methods of Preparation of Haloalkanes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct option is (c) phosphoric acid The explanation is: When ALCOHOLS are heated with potassium or sodium IODIDE in 95% phosphoric acid (H3PO4), iodoalkanes are GENERATED.

Discussion

84.	The heating of 1-Chlorobutane along with alcoholic KOH results in ________(a) elimination of hydrogen from α-carbon atom(b) elimination of hydrogen from β-carbon atom(c) elimination of hydrogen from γ-carbon atom(d) no reactionI have been asked this question in an international level competition.My query is from Haloalkanes & Haloarenes topic in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The CORRECT CHOICE is (b) elimination of hydrogen from β-carbon atom The EXPLANATION: When a HALOALKANE with a β-hydrogen atom is heated with ALC. KOH, it results in a β-elimination reaction to form alkenes.

Discussion

85.	When a reaction proceeds with the retention of configuration, the optical activity of the product will remain same as that of the original reactant.(a) True(b) FalseThe question was asked in a national level competition.This key question is from Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (b) False To elaborate: For example, when (-)-2-methylbutan-1-ol is HEATED with conc. HCl, the product FORMED is (+)-1-chloro-2-methylbutane, which has OPPOSITE optical BEHAVIOUR to that of the reactant.

Discussion

86.	For a particular alkyl group R, what is the correct order of boiling points of the following compounds?(a) RBr > RCl > RF(b) RF > RCl > RBr(c) RCl > RBr > RF(d) RF > RBr > RClI got this question during an interview for a job.I would like to ask this question from Haloarenes Physical Properties topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct OPTION is (a) RBr > RCl > RF To explain I would say: As the size of halogen atom increases, the magnitude of van der WAAL forces increases, that is why RF has the LOWEST boiling point as it is the smallest halogen atom with weakest van der Waal attraction.

Discussion

87.	What is the most suitable temperature for the formation of a diazonium salt from aniline?(a) 0°C(b) 18°C(c) 37°C(d) 60°CI have been asked this question in an interview for internship.Enquiry is from Preparation of Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The CORRECT CHOICE is (a) 0°C The explanation: Diazonium salts are formed by treating ice-cold solution of AROMATIC amines in aqueous mineral acid with SODIUM nitrite at low temperatures of 273-278K.

Discussion

88.	When excess chlorine is used in electrophilic substitution of toluene, which of the following dichloroarenes are formed?(a) ortho and meta(b) ortho and para(c) meta and para(d) ortho, meta and paraI have been asked this question in homework.The origin of the question is Preparation of Haloarenes in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct option is (b) ortho and para The BEST explanation: When excess halogen is USED, the second halogen also gets incorporated into the aromatic ring at ortho and para POSITIONS with respect to the first halogen. This is because the CH3 group in TOLUENE is ortho and para directing.

Discussion

89.	What is the IUPAC name of the following compound?(a) 1-Bromo-3-methylprop-2-ene(b) 3-Bromo-1-methylpropene(c) 1-Bromobut-2-ene(d) 4-Bromobut-2-eneThe question was posed to me in quiz.This intriguing question originated from Haloalkanes Nomenclature topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right choice is (c) 1-Bromobut-2-ene Easiest explanation: The LONGEST chain of C atoms is 4 (butene) and the numbering should begin from the Br side to satisfy the lowest SET of LOCANTS RULE. So, Br is at C-1 and DOUBLE bond is at C-2.

Discussion

90.	Which of the following is not a freon?(a) CCl3F(b) CCl2F2(c) CBr2F2(d) CClF3The question was posed to me in an interview for internship.My doubt stems from Haloalkanes & Haloarenes in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT ANSWER is (c) CBr2F2 For explanation: Freons are chlorofluorocarbon compounds of methane and ethane. The COMPOUND CBr2F2 CONTAINS bromine, and hence is not a FREON.

Discussion

91.	What is the reason for iodoform to be used as an antiseptic?(a) Due to its unpleasant odour(b) Due to its melting point(c) Due to its solubility in alcohol(d) Due to the liberation of free iodineThe question was posed to me in an online interview.I'd like to ask this question from Haloalkanes & Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The CORRECT ANSWER is (d) Due to the liberation of free iodine Explanation: The antiseptic properties of IODOFORM are due to the liberation of free iodine and not due the properties and CHARACTERISTICS of iodoform itself.

Discussion

92.	The major product formed from the dehydrohalogenation of 2-Bromopentane is pent-2-ene.(a) True(b) FalseThis question was posed to me in final exam.This intriguing question originated from Haloalkanes & Haloarenes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right answer is (a) True The best I can EXPLAIN: According to Zaitsev’s rule, the major product will be that ALKENE which has more number of ALKYL groups attached to the DOUBLE bonded CARBON atoms.

Discussion

93.	The process of separation of a racemic mixture into the respective d and l optical isomers is called __________(a) racemisation(b) resolution(c) inversion(d) retentionI had been asked this question during an interview.I need to ask this question from Haloalkanes & Haloarenes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Right choice is (B) resolution To explain I WOULD say: Racemisation is the PROCESS of CONVERTING optical isomers into a racemic mixture and separating them from the mixture is KNOWN as resolution.

Discussion

94.	If a compound does not affect the plane of plane polarised light when passed through it, the compound is said to be _________(a) optically active(b) optically inactive(c) dextrorotatory(d) laevorotatoryThis question was posed to me by my school teacher while I was bunking the class.Query is from Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT choice is (b) optically inactive Best explanation: When the plane of plane polarised light is rotated either to the left or right when PASSED through a compound, it is SAID to be optically ACTIVE. Else, it is optically inactive.

Discussion

95.	Sandmeyer’s reaction can be used to prepare fluoroarenes.(a) True(b) FalseI had been asked this question during a job interview.The doubt is from Preparation of Haloarenes in portion Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct choice is (b) False The explanation: Sandmeyer’s reaction is USED only for PREPARING alkyl chlorides and BROMIDES. Fluoroarenes are prepared by a DIFFERENT method CALLED Balz-Schiemann reaction.

Discussion

96.	As the stability of carbocation formed in the first step of SN1 reaction increases, the rate of the reaction _________(a) increases(b) decreases(c) remains same(d) may increase or decreaseThe question was posed to me in a national level competition.This question is from Haloalkanes & Haloarenes in chapter Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» CORRECT choice is (a) increases To EXPLAIN: GREATER the stability of the carbocation, greater will be the ease of formation from alkyl halide and FASTER will be the reaction rate.

Discussion

97.	Which of the following cannot be a catalyst in the electrophilic substitution of arenes?(a) FeCl3(b) FeBr3(c) NH3(d) AlCl3I had been asked this question in an internship interview.I'm obligated to ask this question of Preparation of Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The CORRECT option is (c) NH3 The best I can explain: The electrophilic substitution of arenes requires the presence of a Lewis ACID catalyst which acts as a halogen CARRIER. NH3 is a Lewis BASE.

Discussion

98.	What is the IUPAC name of the compound shown?(a) 1-Cholor-2-fluorocyclobut-1-ene(b) 2-Chloro-1-fluorocyclobut-1-ene(c) 1-Chloro-2-fluorocyclobut-2-ene(d) 1-Fluoro-2-chlorocyclobut-1-eneI got this question in homework.I would like to ask this question from Haloalkanes Nomenclature topic in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct option is (B) 2-Chloro-1-fluorocyclobut-1-ene For explanation: The alkyl GROUP is alicyclic with 4 carbon ATOMS at the corners of a rectangle and a double bond; hence the base is CYCLOBUTENE. In the case of cyclic alkenes, the position of double bond is always given the first number.

Discussion

99.	In the common naming system, the prefix sym- is used for haloarenes with _____ halogen atoms.(a) 1(b) 2(c) 3(d) 4I got this question in exam.The doubt is from Haloalkanes Nomenclature in division Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» The correct choice is (c) 3 Explanation: The prefix sym- is used for trihaloarenes with same HALOGEN atom at ALTERNATE POSITIONS in the benzene ring (1, 3, 5). The prefixes o-, m- and p- are used for dihaloarenes depending on the RELATIVE positions of the two identical halogen atoms on the aromatic ring.

Discussion

100.	What is the common name of 3-Bromopropene?(a) Tert-Butyl bromide(b) Vinyl bromide(c) Allyl bromide(d) Propylidene bromideI had been asked this question in final exam.Query is from Haloalkanes Nomenclature topic in section Haloalkanes and Haloarenes of Chemistry – Class 12
Answer» Correct choice is (c) Allyl bromide The EXPLANATION is: 3-Bromopropene has 3 C ATOMS in the parent CHAIN with a double bond at C-1 and Br at C-3. This means that Br is ATTACHED to the C which is next to the C-C double bond, hence it is an allylic halide.

Discussion

Explore topic-wise InterviewSolutions in .

The Finkelstein reaction can be used to prepare alkyl fluorides.(a) True(b) FalseI have been asked this question during an online interview.I need to ask this question from Methods of Preparation of Haloalkanes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12

Identify the missing compound Y.(a) NaBr(b) HBr(c) HCl(d) Cu2Br2The question was asked at a job interview.Query is from Preparation of Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12

What is the correct order of reactivity of haloalkanes towards β-elimination reactions?(a) 1°>2°>3°(b) 3°>2°>1°(c) 1°>3°>2°(d) 3°>1°>2°I got this question in homework.Asked question is from Haloalkanes & Haloarenes topic in section Haloalkanes and Haloarenes of Chemistry – Class 12

Chloroform was previously used as a general anaesthetic in surgery.(a) True(b) FalseThe question was asked in an internship interview.The above asked question is from Haloalkanes & Haloarenes topic in division Haloalkanes and Haloarenes of Chemistry – Class 12

Which of the following is a vinylic halide?(a) CH2=CHCHCl2(b) CH3CHClCH3(c) (CH3)2C=CHCH2Cl(d) CH3CH=CClCH2CH3I had been asked this question during an internship interview.My doubt stems from Haloalkanes Classification topic in division Haloalkanes and Haloarenes of Chemistry – Class 12

Which of the following is not a characteristic of CHClF2?(a) Non-toxic(b) Non-flammable(c) Non-corrosive(d) Non-liquefiableThis question was posed to me in examination.I'm obligated to ask this question of Haloalkanes & Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12

2-Chloronitrobenzene is more reactive than chlorobenzene.(a) True(b) FalseThe question was posed to me in an international level competition.My question is taken from Haloalkanes & Haloarenes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12

The compound 2,2-Dichlorobutane is a geminal dihalide.(a) True(b) FalseI had been asked this question during a job interview.I'm obligated to ask this question of Haloalkanes Nomenclature topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12

Carbon tetrarchloride may indirectly cause skin cancer.(a) True(b) FalseThis question was addressed to me in final exam.My question is taken from Haloalkanes & Haloarenes topic in portion Haloalkanes and Haloarenes of Chemistry – Class 12

Which is the largest halogen atom?(a) Bromine(b) Chlorine(c) Fluorine(d) IodineThis question was addressed to me during an interview.I would like to ask this question from Nature of C-X Bond topic in division Haloalkanes and Haloarenes of Chemistry – Class 12

Haloalkanes are more soluble in water than in alcohols.(a) True(b) FalseI got this question in an interview.Question is from Haloarenes Physical Properties in portion Haloalkanes and Haloarenes of Chemistry – Class 12

The compound C6H5F is an example of a ________ halide.(a) allylic(b) benzylic(c) vinylic(d) arylThe question was asked in exam.My question is from Haloalkanes Classification in chapter Haloalkanes and Haloarenes of Chemistry – Class 12

What is the most suitable temperature for the formation of a diazonium salt from aniline?(a) 0°C(b) 18°C(c) 37°C(d) 60°CI have been asked this question in an interview for internship.Enquiry is from Preparation of Haloarenes in division Haloalkanes and Haloarenes of Chemistry – Class 12

Which of the following is not a freon?(a) CCl3F(b) CCl2F2(c) CBr2F2(d) CClF3The question was posed to me in an interview for internship.My doubt stems from Haloalkanes & Haloarenes in portion Haloalkanes and Haloarenes of Chemistry – Class 12

The major product formed from the dehydrohalogenation of 2-Bromopentane is pent-2-ene.(a) True(b) FalseThis question was posed to me in final exam.This intriguing question originated from Haloalkanes & Haloarenes topic in chapter Haloalkanes and Haloarenes of Chemistry – Class 12

Sandmeyer’s reaction can be used to prepare fluoroarenes.(a) True(b) FalseI had been asked this question during a job interview.The doubt is from Preparation of Haloarenes in portion Haloalkanes and Haloarenes of Chemistry – Class 12

In the common naming system, the prefix sym- is used for haloarenes with _____ halogen atoms.(a) 1(b) 2(c) 3(d) 4I got this question in exam.The doubt is from Haloalkanes Nomenclature in division Haloalkanes and Haloarenes of Chemistry – Class 12

What is the common name of 3-Bromopropene?(a) Tert-Butyl bromide(b) Vinyl bromide(c) Allyl bromide(d) Propylidene bromideI had been asked this question in final exam.Query is from Haloalkanes Nomenclature topic in section Haloalkanes and Haloarenes of Chemistry – Class 12