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CBSE Notes 2011-2012

Chemistry: Valuable Questions

Chemistry : Part II For Class XII
Haloalkanes and Haloarenes

(Q.1) Choose the incorrect statement about the benzyl chloride: ( 1 mark )
(a) It is less reactive than alkyl halides.
(b) It can be oxidized to benzaldehyde by boiling with copper nitrate solution.
(c) It is a lachrymatory liquid and answers beilstein’s test.
(d) It gives a white precipitate with alcoholic silver nitrate

(Q.2) Dry ether
The reaction RX + 2Na + RX _______________? R-R + 2NaXis called. ( 1 mark )
(a) Sandmeyer’ reaction
(b) Fittig reaction
(c) Wurtz reaction
(d) Williamson’s synthesis

(Q.3) Substitution of chlorine takes place readily at higher temperature in : ( 1 mark )
(a) CH3CH=CH2
(b) H2C=CH2
(c) HC C
(d) None of the above
View Answer

(Q.4) (CH3)3CMgBr on reaction with D2O gives: ( 1 mark )
(a) (CH3)3CD
(b) (CH3)3COD
(c) (CD3)3CD
(d) (CD3)3OD
View Answer

(Q.5) The silver salt of fatty acid on refluxing with an alkyl halide gives an: ( 1 mark )
(a) Acid
(b) Ester
(c) Ether
(d) Amine
View Answer

(Q.6) Which of the following is the most reactive towards nucleophilic substitution reaction? ( 1 mark )
(a) C6H5Cl
(b) CH2=CHCl
(c) ClCH2CH=CH2
(d) CH3CH=CHCl
View Answer

(Q.7) The molecule with the highest dipole moment is: ( 1 mark )
(a) CH3Cl
(b) CH2Cl2
(c) CHCl3
(d) CCl4
View Answer

(Q.8) C – X bond is strongest in ( 1 mark )
(a)

(b)

(c)

(d)

View Answer

(Q.9) What is added to chloroform to prevent to form phosgene gas: ( 1 mark )
(a) CH3COCH3
(b) C2H5OH
(c) CH3COOH
(d) CH3OH
View Answer

(Q.10) The most reactive nucleophile among the following is: ( 1 mark )
(a) CH3O-
(b) C6H5O-
(c) (CH3)2CHO-
(d) (CH3)3CO-
View Answer

(Q.11) The correct order of decreasing dipole moment is: ( 1 mark )
(a) CH3Cl, CH3Br, CH3F
(b) CH3Cl, CH3F, CH3Br
(c) CH3Br, CH3Cl, CH3F
(d) CH3Br, CH3F, CH3Cl
View Answer

(Q.12) HCl and HI do not give anti- markovnikov’s addition to alkenes in the presence of peroxides because: ( 1 mark )
(a) Both are highly ionic
(b) One is oxidizing and other is reducing
(c) One of the step is endothermic in both the cases
(d) All the steps are exothermic in both the reactions.
View Answer

(Q.13) Which of the following is the correct: ( 1 mark )
(a) RF>RCl>RBr>RI
(b) RF>RBr>RCl>RI
(c) RCl>RBr>RF>RI
(d) RI>RBr>RCl>RF
View Answer

(Q.14) HBr can be added easily to: ( 1 mark )
(a) CH2=CHCl
(b) CH3-CH=CH2
(c) ClCH=CHCl
(d) (CH3)2C=CH2
View Answer

(Q.15) Which of the following is the most reactive towards the SN2 reaction: ( 1 mark )
(a) MeX
(b) RCH2X
(c) R2CHX
(d) R3CX
View Answer

(Q.16) The correct order of Nucleophlicity is: ( 1 mark )
(a) CH3- < NH2- < HO- < F-
(b) NH2- > CH3- > HO- > F-
(c) CH3- > NH2- > HO- > F-
(d) NH2- > F- > HO- > CH3-
View Answer

(Q.17) What are ambident nucleophiles? ( 1 mark )
View Answer

(Q.18) 2-Phenyl-2-chloropropane on treatment with alc.KOH gives mainly: ( 1 mark )
(a) 2-Phenylpropene
(b) 3-Phenylpropene
(c) 1-Phenylpropan-2-ol
(d) 1-Phenylpropan-3-ol
View Answer

(Q.19) When chlorine passed through propene at 400 degree Celsius, the product is: ( 1 mark )
(a) Vinyl chloride
(b) Allyl chloride
(c) PVC
(d) 1,2-dichloroethane
View Answer

(Q.20) The IUPAC name of CH3-CH=CHCH2Br is: ( 1 mark )
(a) 1-Bromo-2-butene
(b) 1-Bromo-3-butene
(c) 2-Butene-1-bromide
(d) 4-Bromo-2-butene
View Answer

(Q.21) Why is sulphuric acid not used during the reactions of alcohols with KI? ( 1 mark )
View Answer

(Q.22) Write the IUPAC name of the following compound.
ClCH2CHClCH3 ( 1 mark )
View Answer

(Q.23) Which is a better nucleophile, a bromide ion or iodide ion? ( 1 mark )
View Answer

(Q.24) How will youget 1-bromopropane from propene? ( 1 mark )
View Answer

(Q.25) Write the structure of 2-Chloro-3-methylpentane. ( 1 mark )
View Answer

(Q.26) What is the nature of C-X bond of haloalkanes? ( 1 mark )
View Answer

(Q.27) Arrange the compounds of each set in order of reactivity towards SN2 displacement:
2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane. ( 1 mark )
View Answer

(Q.28) What is an asymmetric carbon? ( 1 mark )
View Answer

(Q.29) Which haloalkane has the maximum density and why? ( 1 mark )
View Answer

(Q.30) What is Freon? ( 1 mark )
View Answer

(Q.31) Write the full form of DDT. ( 1 mark )
View Answer

(Q.32) Write a chemical reaction to illustrate Saytzeff’s rule. ( 1 mark )
View Answer

(Q.33) Write the IUPAC name of the following structure. CH2BrCH=CHCH2CHCl2 ( 1 mark )
View Answer

(Q.34) Arrange the following in increasing order of boiling point.
CH3CH2CH2CH2Br, (CH3)3CBr, (CH3)2CHCH2Br. ( 1 mark )
View Answer

(Q.35) Explain why thionyl chloride reaction is preferred forpreparing alkyl chlorides from alcohols? ( 1 mark )
View Answer

(Q.36) Arrange the following in order of their decreasing reactivity in nucleophile substitution reactions:
CH3F, CH3I, CH3Br, CH3Cl. ( 1 mark )
View Answer

(Q.37) Define optical activity? ( 1 mark )
View Answer

(Q.38) What are enantiomers? ( 1 mark )
View Answer

(Q.39) What is racemic mixture or racemic modification? ( 1 mark )
View Answer

(Q.40) Define retention? ( 1 mark )
View Answer

(Q.41) The conversion of 2,3-dibromobutane to 2-butene with Zn and alcohol is a: ( 1 mark )
(a) Redox reaction
(b) Alpha-elimination
(c) Beta- elimination
(d) Both redox and Beta-elimination
View Answer

(Q.42) Vicinal and gem dihalides can be distinguished by: ( 1 mark )
(a) aq. KOH
(b) Zn dust
(c) alc. KOH
(d) Br2
View Answer

(Q.43) Which of the following have the highest boiling point: ( 1 mark )
(a) Chlorobenzene
(b) o-Dichlorobenzene
(c) m-Dichlorobenzene
(d) p-Dichlorobenzene
View Answer

(Q.44) The most suitable reaction for the preparation of n-propylbenzene is: ( 1 mark )
(a) Friedel-crafts reaction
(b) Wurtz reaction
(c) Wurtz-fitting reaction
(d) Grignard reaction
View Answer

(Q.45) Chlorobenzene can be obtained from benzene diazonium chloride by: ( 1 mark )
(a) Gattermann’s reaction
(b) friedel craft reaction
(c) Wurtz reaction
(d) Fittig reaction
View Answer

(Q.46) Most reactive halide towards SN1 reaction is ( 1 mark )
(a) n-Butyl chloride
(b) sec-Butyl chloride
(c) tert-Butyl chloride
(d) Allyl chloride
View Answer

(Q.47) When HBr is added to propene in the absence of peroxides, in the first step there is the addition of: ( 1 mark )
(a) H+
(b) Br –
(c) H
(d) Br
View Answer

(Q.48) In the presence of benzoylperoxide propene reacts with HCl gas. The product is: ( 1 mark )
(a) 2-chloropropane
(b) Allyl chloride
(c) No reaction
(d) n-Propyl chloride
View Answer

(Q.49) Cl2reacts with CS2in presence of I2to form ( 1 mark )
(a) CHCl3
(b) CCl4
(c) C2H5Cl
(d) Cl3C – NO2
View Answer

(Q.50) If chloroform is left open in air in the presence of sunlight, it gives ( 1 mark )
(a) Carbon tetrachloride
(b) Carbonyl chloride
(c) Mustard gas
(d) Lewisite
View Answer

(Q.51) 1,2-dichloroethane is known to exhibit. ( 1 mark )
(a) Optical isomerism
(b) Geometrical isomerism
(c) Metamerism
(d) Tautomerism
View Answer

(Q.52) 2-Bromopentane is heated with potassium ethoxide in ethanol. The major product obtained is ( 1 mark )
(a) 2-Ethoxypentane
(b) Pentene-1
(c) cis-Pentene-2
(d) trans-Pentene-2
View Answer

(Q.53) The reactivity order of halides for dehydrohalogenation is ( 1 mark )
(a) R – F > R – Cl > R – Br > R – I
(b) R – I > R – Br > R – Cl > R – F
(c) R – I > R – Cl > R – Br > R – F
(d) R – F > R – I > R – Br > R – Cl
View Answer

(Q.54)
Which of the following is correct ? ( 1 mark )
(a) A and B are same and C is different
(b) A and C are same and B is different
(c) A, B and C are same
(d) B and C are same and A is different
View Answer

(Q.55) In reaction, recemization takes place. It is due to
( 1 mark )
(a) inversion of configuration
(b) retention of configuration
(c) conversion of configuration
(d) both (a) & (b)
View Answer

(Q.56) Identify Z in

( 1 mark )
(a) Mixture of CH3CHClCH2Cl and CH3CHOHCH2Cl
(b) CH3CHOHCH2Cl
(c) CH3CHClCH2OH
(d) CH3CHClCH2Cl
View Answer

(Q.57) The reaction of with CuCl gives
( 1 mark )
(a)
(b)
(c)

CH3I
(d) C2H5Cl
View Answer

(Q.74) obtained by chlorination of n-butane, will be
( 1 mark )
(a) meso-form
(b) racemic mixture
(c) d-form
(d) I-form
View Answer

(Q.75) Hydrocarbon A reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon atoms. A is: ( 1 mark )
(a) CH2=CH2
(b) HC C
(c) CH4
(d) CH3-CH3
View Answer

(Q.76) Which of the following will have the maximum dipole moment? ( 1 mark )
(a)
(b)
(c)
(d)
View Answer

(Q.77) alc.KOH
In the reaction CH3HC2I ______________? X ________? Y ________? Z, Z is: ( 1 mark )
(a) CH3CH2CN
(b) CNCH2CH2CN
(c) BrCH2CH2CN
(d) BrCH=CHCN
View Answer

(Q.78) The order of reactivity of alkyl halides towards elimination reaction is ( 1 mark )
(a) 3° > 2° > 1°
(b) 2° > 1° > 3°
(c) 3° > 1° > 2°
(d) 1° > 2° > 3°
View Answer

(Q.79) When primary amine reacts with chloroform in ethanolic KOH, then the product is ( 1 mark )
(a) an isocyanide
(b) an aldehyde
(c) a cyanide
(d) an alcohol
View Answer

(Q.80) The starting substance for the preparation of iodoform is any one of the following, except ( 1 mark )
(a)

(b)

(c)
(d)
View Answer

(Q.81) Freon-12 is commonly used as ( 1 mark )
(a) Insecticide
(b) Refrigerant
(c) A solvent
(d) A fire extinguisher
View Answer

(Q.82) mechanism proceeds through intervention of ( 1 mark )
(a) Carbonium ion
(b) Transition state
(c) Free radical
(d) Carbanion
View Answer

(Q.83) Match list I (compound) with list II (use) and select the correct answer using the codes given below the lists :

List I List II
I. Acetylsalicylic acid A. Insecticide
II. DDT B. Drug
III. Naphthalene C. Moth repellent
IV. Carbon tetra-chloride D. Fire extinguisher
E. Refrigerant ( 1 mark )
(a) I-B, II-A, III-C, IV-D
(b) I-E, II-C, III-D, IV-A
(c) I-B, II-C, III-D, IV-A
(d) I-E, II-A, III-C, IV-D
View Answer

(Q.84) Which of the following will give vinyl chloride ? ( 1 mark )
(a)
(b)
(c)
(d) All
View Answer

(Q.85) Identify the set of reagent/reaction conditions 'X' and 'Y' in the following set of transformations:

( 1 mark )
(a) X = dilute aqueous NaOH, 20°C; Y = HBr / acetic acid, 20°C
(b) X = concentrated alcoholic NaOH, 80°C; Y = HBr / acetic acid, 20°C
(c) X = dilute aqueous NaOH, 20°C; Y = Br2/ CHCl3, 0°C
(d) X = concentrated alcoholic NaOH, 80°C; Y = Br2/ CHCl3, 0°C
View Answer

(Q.86) The reaction of benzyl chloride with sodium cyanide followed by reduction with hydrogen in the presence of nickel gives ( 1 mark )
(a) -Phenylethylamine
(b) N-Isobutylaniline
(c) Benzylamine
(d) Aniline
View Answer

(Q.87) When chlorine is passed through propene at 400°C, which of the following is formed? ( 1 mark )
(a) PVC
(b) Allyl chloride
(c) Vinyl chloride
(d) 1,2-Dichloroethane
View Answer

(Q.88) SN2 mechanism proceeds through the intervention of: ( 1 mark )
(a) Carbonium ion
(b) Transition state
(c) Free radical
(d) Carbanion
View Answer

(Q.89) Chloroform on treatment with alc.KOH and aniline gives: ( 1 mark )
(a) Phenyl isocyanide
(b) Phenol
(c) Cyanobenzene
(d) None of these
View Answer

(Q.90) The product of reaction of alcoholic silver nitrate with ethyl bromide is: ( 1 mark )
(a) Ethylene
(b) Ethyl nitrite
(c) Nitro ethane
(d) Ethyl alcohol
View Answer

(Q.91) In the reaction CH3CHCl2 intermediate X, X is
( 1 mark )
(a) CH3CHO
(b) (CH3)2CO
(c) CH3CH2OH
(d) HO-CH2CH2OH
View Answer

(Q.92) Which of the following will have zero dipole moment? ( 1 mark )
(a) 1,1-Dichloroethylene
(b) cis-1,2-Dichloroethylene
(c) trans-1,2-Dichloroethylene
(d) none of these
View Answer

(Q.93) Only two isomeric monochloro derivatives are possible for: ( 1 mark )
(a) n-hexane
(b) 2,4-Dimethylpentane
(c) benzene
(d) 2-methylpropane
View Answer

(Q.94) Alkyl halide on treatment with alc. KOH gives: ( 1 mark )
(a) Alcohols
(b) Alkenes
(c) Alkanes
(d) Aldehydes
View Answer

(Q.95) Chlorination of toluene in the presence of light and heat followed by treatment with aqueous NaOH gives: ( 1 mark )
(a) o-cresol
(b) p-cresol
(c) 2,4-Dihydroxytoluene
(d) Benzoic acid
View Answer

(Q.96) Which of the following can not be used in friedel-crafts reaction: ( 1 mark )
(a) FeCl3
(b) FeBr3
(c) AlCl3
(d) NaCl
View Answer

(Q.97) The fire extinguisher with brand name Pyrene is chemically ( 1 mark )
(a) Dichloromethane.
(b) Trichloromethane.
(c) Tetrachloromethane.
(d) Geminal dichloride.
View Answer

(Q.98) Reimer-Tiemann reaction involving chloroform produces ( 1 mark )
(a) Salicylic acid.
(b) Benzoic acid.
(c) Salicyladehyde.
(d) Benzaldehyde.
View Answer

(Q.99) Primary and secondary chloroalkanes are prepared by passing HCl gas through a suitable alcohol in the presence of anhydrous zinc chloride. This reaction is known as ( 1 mark )
(a) Swarts reaction.
(b) Finkelstein reaction.
(c) Borodine reaction.
(d) Grove reaction.
View Answer

(Q.100) Breathing about 900 ppm of chloroform for a short time can cause dizziness, fatigue and headache. The part of body that metabolizes chloroform to phosgene is ( 1 mark )
(a) Kidneys.
(b) Gall bladder.
(c) Pancreas.
(d) Liver.
View Answer

(Q.101) In the Grove’s process, chloroalkanes are prepared by passing HCl gas through a suitable alcohol in the presence of anhydrous zinc chloride. The purpose of using zinc chloride is ( 1 mark )
(a) to help in the cleavage of C-C bond.
(b) to help in the cleavage of C-H bond.
(c) to help in the cleavage of C-O bond.
(d) to provide the reaction with moisture free conditions.
View Answer

(Q.102) The chlorobenzene is commercially prepared by Raschig’s process in which a mixture of benzene vapours, air and hydrogen chloride is passed over heated ( 1 mark )
(a) Copper powder.
(b) Cuprous chloride.
(c) Cupric chloride.
(d) Alumina.
View Answer

(Q.103) Bromoalkanes are obtained by refluxing a suitable alcohol with constant boiling hydrobromic acid in the presence of conc. H2SO4 as catalyst. The constant boiling HBr has aqueous composition of ( 1 mark )
(a) 48%.
(b) 58%.
(c) 68%.
(d) 78%.
View Answer

(Q.104) Iodoform was earlier used as an antiseptic for dressing wounds, its antiseptic properties are due to liberation of a substance when iodoform comes in contact with skin, the substance is ( 1 mark )
(a) Phosgene.
(b) Iodine.
(c) Chlorine.
(d) Hydrogen iodide.
View Answer

(Q.105) The addition of hydrogen halides to an unsymmetrical alkenes takes place according to ( 1 mark )
(a) SN1 mechanism.
(b) SN2 mechanism.
(c) Markownikoff’s Rule.
(d) Saytzeff’s Rule.

View Answer

(Q.106) The alkyl halide that depletes the ozone layer significantly is ( 1 mark )
(a) Monochloromethane.
(b) Dichloromethane.
(c) Trichloromethane.
(d) Tetrachloromethane.
View Answer

(Q.107) For the same alkyl group, the boiling points of haloalkanes decreases in the order ( 1 mark )
(a) RF>RCl>RBr>RI.
(b) RCl>RBr>RI>RF.
(c) RBr>RI>RF>RCl.
(d) RI>RBr>RCl>RF.
View Answer

(Q.108) Most widely used refrigerant freon (freon-12) is prepared by ( 1 mark )
(a) Etard’s reaction.
(b) Swarts reaction.
(c) Finkelstein reaction.
(d) Birnbaum-Simonini reaction.
View Answer

(Q.109) Cinnamyl chloride is ( 1 mark )
(a) 3-Chloro-1-phenylprop-1-ene.
(b) 2-Chloro-1-phenylprop-2-ene.
(c) 1-Chloro-3-phenylprop-1-ene.
(d) 2-Chloro-3-phenylprop-2-ene.
View Answer

(Q.110) DDT was first prepared in 1873 but it was not until 1939 that Paul Muller at Geigy pharmaceuticals in Switzerland, discovered the effectiveness of DDT as an insecticide, he was awarded Noble Prize for this discovery in 1948 in subject ( 1 mark )
(a) Chemistry.
(b) Medicines and Physiology.
(c) Biochemistry.
(d) Pharmaceuticals.
View Answer

(Q.111) The DDT is prepared by heating chlorobenzene with chloral in the presence of conc. H2SO4, the chloral is ( 1 mark )
(a) Trichloroacetaldehyde.
(b) Dichloroacetaldehyde.
(c) Trichloroacetone.
(d) Dichloroacetone.
View Answer

(Q.112) The markownikoff’s rule reverses in the presence of peroxide, but this is possible only in case of ( 1 mark )
(a) HI.
(b) HBr.
(c) HCl.
(d) HF.
View Answer

(Q.113) Dehydrohalogenation or elimination reactions of alkyl halides having strongly acidic ?-hydrogen takes place through ( 1 mark )
(a) E1 mechanism.
(b) E2 mechanism.
(c) E1cB mechanism.
(d) Benzyne mechanism.
View Answer

(Q.114) The nucleophilicity order of different halide ions is as ( 1 mark )
(a) I->Br->Cl->F-.
(b) Br->Cl->F->I-.
(c) Cl->F->I->Br-.
(d) F->I->Br->Cl-.
View Answer

(Q.115) When chlorobenzene is treated with NaNH2 in liquid ammonia at 196K, aniline is formed. This reaction takes place by ( 1 mark )
(a) E1 mechanism.
(b) E2 mechanism.
(c) E1cB mechanism.
(d) Benzyne mechanism.
View Answer

(Q.116) During the preparation of iodoalkanes a suitable alcohol is refluxed with constant boiling hydriodic acid (57%). HI may also be prepared in situ by the action of ( 1 mark )
(a) Phosphoric acid on KI.
(b) Sulphuric acid on KI.
(c) Phosphoric acid on KIO3.
(d) Sulphuric acid on KIO3.
View Answer

(Q.117) A copper strip is heated strongly in Bunsen flame till it ceases to impart any greenish or bluish flame, then a pinch of organic halide is placed on this hot strip and reintroduced into the flame, if a green or bluish green flame reappears it indicates the presence of halogen but does not confirm the nature of halogen. This test is ( 1 mark )
(a) Lassaigne’s test.
(b) Mollisch’s test.
(c) Victor Mayer test.
(d) Beilstein test.
View Answer

(Q.118) Williamson’s synthesis is a nucleophilic substitution reaction of alkyl halides which results in the formation of ( 1 mark )
(a) Esters.
(b) Ethers.
(c) Amides.
(d) Acid anhydrides.
View Answer

(Q.119) The incorrect statement about DDT is ( 1 mark )
(a) The problems related to extensive use of DDT began to appear in early 1970s.
(b) Many species of insects developed resistance to DDT and it was also discovered to have high toxicity towards fish.
(c) The chemical stability of DDT and its fat solubility further increased the problems.
(d) DDT is not completely biodegradable and gets deposited in fatty tissues, its use has been banned in USA since 1973.
View Answer

(Q.120) The allylic bromination can be carried out with the help of ( 1 mark )
(a) N-bromosuccinic acid.
(b) N-bromosalicylic acid.
(c) N-bromosalicylamide.
(d) N-bromosuccinimide.
View Answer

(Q.121) If in lassaigne’s test, AgNO3 reacts with lassaigne’s extract to give white ppt that are soluble in NH4OH, it indicates the presence of ( 1 mark )
(a) Fluorine.
(b) Chlorine.
(c) Bromine.
(d) Iodine.
View Answer

(Q.122) The nucleophilic substitution of halide group with isocyanide group can be affected by reacting alky halide with ( 1 mark )
(a) NaCN.
(b) KCN.
(c) AgCN.
(d) LiCN.
View Answer

(Q.123) Quantitative estimation of active hydrogens in an organic compound can be done by ( 1 mark )
(a) Lassaigne’s method.
(b) Mollisch’s method.
(c) Victor Mayer method.
(d) Zerewitnoff’s method.
View Answer

(Q.124) Benzal chloride is ( 1 mark )
(a) 1,2-Dichloro-1-phenylethane.
(b) 1,1-Dichloro-1-phenylmethane.
(c) 1,1-Dichloro-2-phenylethane.
(d) 1,1,1-Trichloro-1-phenylmethane.
View Answer

(Q.125) Aryl chlorides can also prepare Grignard reagents but solvent used instead of ether (used for alkyl chlorides) is ( 1 mark )
(a) Pyridine.
(b) Methanol.
(c) Ethanol.
(d) Tetrahydrofuran.
View Answer

(Q.126) Walden inversion takes place in ( 1 mark )
(a) Free radical mechanisms.
(b) Electrophilic mechanisms.
(c) SN1 mechanisms.
(d) SN2 mechanisms.
View Answer

(Q.127) Preparation of alkyl fluorides by heating suitable chloro or bromoalkanes with inorganic fluorides such as AsF3, SbF3, CoF3, AgF, Hg2F2 etc. is known as ( 1 mark )
(a) Etard’s reaction.
(b) Swarts reaction.
(c) Mendius reaction.
(d) Birnbaum-Simonini reaction.
View Answer

(Q.128) Halogenation of alkanes that is reversible is ( 1 mark )
(a) Fluorination.
(b) Chlorination.
(c) Bromination.
(d) Iodination.
View Answer

(Q.129) The dehydrohelogenation of haloalkanes results in the formation of ( 1 mark )
(a) an alkane.
(b) an alkene.
(c) an alkyne.
(d) an aromatic hydrocarbon.
View Answer

(Q.130) The optimum temperature for allylic halogenation of alkenes is ( 1 mark )
(a) 473K.
(b) 573K.
(c) 673K.
(d) 773K.
View Answer

(Q.131) The most convenient method for the preparation of haloalkanes involves the substitution of –OH group of an alcohol by the halogen atom. For a given alcohol, the reactivity of halogen acids decreases in the order ( 1 mark )
(a) HCl>HBr>HI.
(b) HBr>HI>HCl.
(c) HI>HCl>HBr.
(d) HI>HBr>HCl.
View Answer

(Q.132) PBr3 and PI3 used for the preparation of alkyl halides from alcohols, are not very stable compounds, these are generally prepared in situ by the action of a substance on bromine and iodine respectively, the substance is ( 1 mark )
(a) Red phosphorous.
(b) White phosphorous.
(c) Potassium iodide.
(d) Silver iodide.
View Answer

(Q.133) If the structure of alkyl halide during dehydrohalogenation reaction is such that it can undergo H-elimination from two different sites, then the more highly substituted alkene is the major product. This generalization is known as ( 1 mark )
(a) Markownikoff’s Rule.
(b) Saytzeff’s Rule.
(c) Kharasch’s effect.
(d) Racemization.
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(Q.134) Side chain-halogenation of haloarenes is a reaction having ( 1 mark )
(a) SN1 mechanism.
(b) SN2 mechanism.
(c) Free radical mechanism.
(d) Benzyne mechanism.
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(Q.135) The iodoalkanes can be prepared from corresponding chloro or bromoalkanes by heating with NaI in acetone or methanol, this reaction is called as ( 1 mark )
(a) Etard’s reaction.
(b) Swarts reaction.
(c) Finkelstein reaction.
(d) Birnbaum-Simonini reaction.
View Answer

(Q.136) The sandmeyar reaction is modified to gattermann reaction by using a mixture of freshly prepared copper powder in the presence of halogen acid instead of cuprous halide dissolved in corresponding halogen acid (sandmeyer reaction), the yield of gattermann reaction is around ( 1 mark )
(a) 40%.
(b) 60%.
(c) 80%.
(d) 90%.
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(Q.137) Victor Grignard discovered Grignard reagents (RMgX) in1900, for this discovery, he was awarded Noble Prize in chemistry in ( 1 mark )
(a) 1902.
(b) 1912.
(c) 1922.
(d) 1932.
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(Q.138) Alkyl halides are converted into ethers by Williamson’s synthesis, another way to convert alkyl halides into ethers is by using ( 1 mark )
(a) Silver hydroxide.
(b) Sodium hydroxide.
(c) Dry silver oxide.
(d) Sodium peroxide.
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(Q.139) For the nucleophilic substitution of –OH group by halide ion during the preparation of haloalkanes from alcohols, the reactivity order of different alcohols is ( 1 mark )
(a) tertiary>secondary>primary.
(b) secondary>primary>tertiary.
(c) primary>tertiary>secondary.
(d) tertiary>primary>secondary.
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(Q.140) When the aqueous ethanolic solution of a haloalkane (particularly iodoalkanes) is heated with silver cyanide, the chief product formed is ( 1 mark )
(a) Alkyl cyanides.
(b) Alkyl isocyanides.
(c) Alkyl cyanates.
(d) Alkyl isocyanates.
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(Q.141) Due to prevailing basic conditions of the reaction, the Wurtz reaction is not responded by ( 1 mark )
(a) Tertiary alkyl halides.
(b) Secondary alkyl halides.
(c) Primary alkyl halides.
(d) Sodium metal.
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(Q.142) In Borodine-Hunsdiecker reaction, bromoalkanes are prepared by refluxing the silver salt of a fatty acid with bromine in ( 1 mark )
(a) Ethanol.
(b) Acetone.
(c) Diethyl ether.
(d) Carbon tetrachloride.
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(Q.143) Tetraethyl lead (TEL) is an important antiknocking agent in gasoline used for running vehicles, it is prepared by reacting alkyl halide with an alloy of lead in the presence of dry ether, the alloy of lead is ( 1 mark )
(a) Li-Pb.
(b) Na-Pb.
(c) Hg-Pb.
(d) Zn-Pb.
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(Q.144) The incorrect explanation to the low reactivity of aryl halides in comparison to that of alkyl halides is ( 1 mark )
(a) Resonance effect.
(b) Difference in hybridization of carbon atoms in C-X bond.
(c) Polarity of C-X bond.
(d) +I effect of benzene ring.
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(Q.145) The silver salts of carboxylic acids on refluxing with I2 dissolved in CCl4 gives esters of carboxylic acid instead of iodoalkanes. This reaction is known as ( 1 mark )
(a) Etard’s reaction.
(b) Swarts reaction.
(c) Finkelstein reaction.
(d) Birnbaum-Simonini reaction.
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(Q.146) The Dow’s process is used for the preparation of ( 1 mark )
(a) Chlorobenzene.
(b) Fluorobenzene.
(c) Bromobenzene.
(d) Phenol.
View Answer

(Q.147) Organohalogen compound amongst the following that is used as an anaesthetic agent is ( 1 mark )
(a) Chloramphenicol.
(b) Chloroquine.
(c) Chloromycetin.
(d) Halothane.
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(Q.148) Picric acid is ( 1 mark )
(a) 2,4,6-Trinitrotoluene
(b) 2,4,6-Trinitroaniline.
(c) 2,4,6-Trinitrophenol.
(d) 1,3,5-Trinitrobenzene.
View Answer

(Q.149) The benzene diazonium chloride needed for the sandmeyer reaction to produce aromatic halides is produced by diazotisation reaction that takes place at ( 1 mark )
(a) 0-50C.
(b) 5-100C.
(c) 10-150C.
(d) 15-200C.
View Answer

(Q.150) The metallic powder that is used in Ullmann synthesis of diphenyl is ( 1 mark )
(a) Manganese powder.
(b) Chromium powder.
(c) Magnesium powder.
(d) Copper powder.
View Answer

(Q.151) When phosphorous trihalide is reacted with a suitable alcohol to form haloalkane, the side product of reaction is ( 1 mark )
(a) Hypophosphorous acid.
(b) Phosphorous acid.
(c) Phosphoric acid.
(d) Pyrophosphoric acid.
View Answer

(Q.152) The reaction amongst the following that does not involve the use of aryl halides is ( 1 mark )
(a) Wurtz reaction.
(b) Wurtz-Fittig reaction.
(c) Fittig reaction.
(d) Ullmann reaction.
View Answer

(Q.153) The allylic chlorination is generally done with chlorine at 773K, but it can also be carried out at lower temperature with the help of ( 1 mark )
(a) CuCl/HCl.
(b) Cu/HCl.
(c) HCl.
(d) SO2Cl2.

View Answer

(Q.154) The chlorobenzene can be converted into benzene by reduction with nascent hydrogen produced by an alloy(metallic) in the presence of alkali, the metallic alloy used is ( 1 mark )
(a) Cd-Al.
(b) Ni-Cd.
(c) Hg-Cd.
(d) Ni-Al.
View Answer

(Q.155) The thionyl chloride method is preferred over hydrogen chloride or phosphorous chloride method for the preparation of haloalkanes because both the by-products (SO2 and HCl) in this case are gases and escape leaving behind pure chloroalkane. This reaction takes place in the presence of ( 1 mark )
(a) Conc. sulphuric acid.
(b) Phosphoric acid.
(c) Anhydrous zinc chloride.
(d) Pyridine.
View Answer

(Q.156) The poisonous gas phosgene is chemically ( 1 mark )
(a) Thionyl chloride.
(b) Carbonyl chloride.
(c) Sulphonyl chloride.
(d) Sulphuryl chloride.
View Answer

(Q.157) The fluoroarenes are prepared by heating the corresponding diazonium tetrafluoroborates that are in turn obtained by diazotisation of suitable primary amine with aqueous NaNO2 in the presence of fluoroboric acid (HBF4) at 273-278K. This reaction is known as ( 1 mark )
(a) Balz-Schiemann reaction.
(b) Swarts reaction.
(c) Finkelstein reaction.
(d) Birnbaum-Simonini reaction.
View Answer

(Q.158) The optimum temperature required for the Riemer-Tiemann reaction is ( 1 mark )
(a) 240K.
(b) 340K
(c) 440K
(d) 540K
View Answer

(Q.159) The substance that is added to destroy traces of phosgene formed by aerial oxidation of chloroform on prolonged storage is ( 1 mark )
(a) Ether.
(b) Ester.
(c) Alcohol.
(d) Carboxylic acid.
View Answer

(Q.160) The reaction of haloalkanes with aqueous sodium or potassium hydroxide or moist silver oxide to produce alcohols is an example ( 1 mark )
(a) Elimination reaction.
(b) Dehalogenation reaction.
(c) Reduction reaction.
(d) Hydrolysis reaction.
View Answer

(Q.161) The hydride ion transfer takes place at each step in the reduction done by using ( 1 mark )
(a) H2 in the presence of Nickel.
(b) Sodium in the presence of ethanol.
(c) LiAlH4.
(d) Zn and NH4OH.
View Answer

(Q.162) Grignard reagents (RMgX) are potential sources of carbanions because of ( 1 mark )
(a) polar C-Mg bond.
(b) +I effect of alkyl group.
(c) solvent properties of ether with which it is stored.
(d) their ability of react in any medium.
View Answer

(Q.163) The maximum dipole moment amongst the different halomethanes is that of ( 1 mark )
(a) CH3F.
(b) CH3Cl.
(c) CH3Br.
(d) CH3I.
View Answer

(Q.164) Refluxing is ( 1 mark )
(a) Continuous heating of a liquid at isothermal conditions.
(b) Adiabatic heating of liquid in an isolated system.
(c) Adiabatic heating of liquid in an isolated system.
(d) The process of heating a liquid in a flask with a condenser so that the vapours are condensed back into the same flask.
View Answer

(Q.165) Alkyl halide with Garlic like odour is ( 1 mark )
(a) vinyl chloride.
(b) methyl iodide.
(c) benzyl iodide.
(d) allyl iodide.
View Answer

(Q.166) Westron is a highly toxic halogen derivative liquid used as fumigant and insecticide formed the reaction of acetylene with the halogen that is ( 1 mark )
(a) Fluorine.
(b) Chlorine.
(c) Bromine.
(d) Iodine.
View Answer

(Q.167) Teflon is a white, dense, highly crystalline, extremely inert compound. Chemically it is ( 1 mark )
(a) poly monochlorotrifuoroethylene.
(b) poly monofluorotrichloroethylene.
(c) poly tetrafluoroethylene.
(d) poly tetrachloroethylene.
View Answer

(Q.168) The fluorinating agent generally used for the preparation of Freon-12 is ( 1 mark )
(a) MgF2.
(b) WF3.
(c) TiF4.
(d) SbF5.
View Answer

(Q.169) A hydrocarbon C5H10 does not react with chlorine but gives a single monochloro compound, C5H9Cl in bright sunlight. Identify the hydrocarbon. ( 2 Marks )
View Answer

(Q.170) Identify isomers are possible monochloro structural isomers that would be expected to form on free radical chlorination of
(CH3)2CHCH2CH3. ( 2 Marks )
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(Q.171) Write the Finkelstein reaction. ( 2 Marks )
View Answer

(Q.172) Complete the following reactions:
(a) C6H5ONa + C2H5Cl --------à
(b) CH3CH2CH2OH + SOCl2 -------à ( 2 Marks )
View Answer

(Q.173) p-dichlorobenzene has higher melting point and lower solubility than o- and m-isomer. Explain? ( 2 Marks )
View Answer

(Q.174) How will you bring about the following conversions?
(a) Ethane to bromoethane
(b) 1-Chlorobutane to n-octane ( 2 Marks )
View Answer

(Q.175) Identify chiral and achiral molecules in each of the following pair of compounds.

( 2 Marks )
View Answer

(Q.176) Haloalkanes react with aqueous KOH to form alcohols but react with alcoholic KOH to form alkenes. Why? ( 2 Marks )
View Answer

(Q.177) Write the Sandmeyer reaction. ( 2 Marks )
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(Q.178) How will you prepare DDT? ( 2 Marks )
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(Q.179) Identify the A and B in following reaction:

( 2 Marks )
View Answer

(Q.180) Write the mechanism of the following reaction:
nBuBr + KCN nBuCN
( 2 Marks )
View Answer

(Q.181) Explain why alkyl halides are generally not prepared in the laboratory by free radical halogenation of alkanes. ( 2 Marks )
View Answer

(Q.182) CHF3 is less acidic than CHCl3. Why? ( 2 Marks )
View Answer

(Q.183) How the following conversions can be carried out?
(a) 1-Bromopropane to 2-bromopropane
(b) Aniline to chlorobenzene
(c) Benzene to diphenyl ( 3 Marks )
View Answer

(Q.184) Haloalkanes undergo nucleophilic substitutions whereas haloarenes undergo electrophilic substitutions. Why? ( 3 Marks )

(Q.185) Explain why?
(a) Alkyl halides, though polar, are immiscible with water.
(b) Grignard reagents should be prepared under anhydrous conditions? ( 3 Marks )

(Q.186) Write the following name reactions.
(a) Friedal-Crafts acylation.
(b) Friedal-Crafts alkylation.
(c) Wurtz-Fittig reaction. ( 3 Marks )

(Q.187) Write the following name reactions.
(a) Gattermann reaction.
(b) Balz-Schiemann reaction.
(c) Hunsdiecker reaction.

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Answer key

Please make available an answer key for the above questions so that they can be graded appropriately.

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Chemistry

These really are very imp question from every pt of view.
But, please tell me the answer of 89 question.
How exactly the reaction wud take place?