InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Amongst the following the most basic compound isA. BenzylamineB. AnilineC. AcetanilideD. p-nitroaniline |
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Answer» Correct Answer - A `-NH_2` group is not linked with benzene ring |
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| 2. |
Which hydrocarbon will be most stableA. MethaneB. EthaneC. PropaneD. Butane |
| Answer» Correct Answer - D | |
| 3. |
Iso-octane is mixed to the petrolA. To precipitate inorganic substancesB. To prevent freezing of petrolC. To increase boiling point of petrolD. As an antiknock |
| Answer» Correct Answer - D | |
| 4. |
Amongst the following , the one which can exist in free state as a stable compound isA. `C_7H_9O`B. `C_8H_12O`C. `C_6H_11O`D. `C_10H_17O_2` |
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Answer» Correct Answer - B Degree of unsaturation = `(Sigman(v-2))/2+1` n=no. of atoms of a particular type v=valency of the atom `C_7H_9O: DU=(7(4-2)+9(1-2)+1(2-2))/2 +1 =3.5` `C_8H_12O : DU=(8(4-2)+12(1-2)+1(2-2))/2 +1=3` `C_6H_11O :DU=(6(4-2)+1(1-2)+1(2-2))/2 +1=1.5` `C_10H_17O_2 : DU=(10(4-2)+17(1-2)+2(2-2))/2 +1=2.5` Molecules with fractional degree of unsaturation cannot exist with stability |
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| 5. |
In the commercial gasolines, the type of hydrocarbons which are more desirable isA. Branched hydrocarbonB. Straight-chain hydrocarbonC. Linear unsaturated hydrocarbonD. Toluene |
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Answer» Correct Answer - A Branched hydrocarbons are more desirable because they are more volatile and have high octane number. |
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| 6. |
Which of the following alkenes gives only acetic acid on oxidation with potassium permanganate solutionA. EthyleneB. 1-buteneC. PropeneD. 2-butene |
| Answer» Correct Answer - C | |
| 7. |
An organic compound reacts with `Cu_2Cl_2` and also decolourise `Br_2` water isA. `CH_3-C-=C-CH_3`B. `CH_2=CH-CH_3`C. `CH_3-C-=CH`D. `CH_3-CH_3` |
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Answer» Correct Answer - C Alkenes and alkynes both decolourise bromine water, but only alkynes , containing terminal H atom reacts with ammonical cuprous chloride solution. `CH_3-C-=Chunderset(H_2O)overset(Br_2)to CH_3-undersetunderset(Br)(|)C=CHBr underset(H_2O)overset(Br_2)to CH_3-undersetunderset(Br)(|)oversetoverset(Br)(|)C-undersetunderset(Br)(|)overset(Br)overset(|)C` `CH_3-C-=underset(Cu_2Cl_2)overset"ammonical"to CH_3-C-=C Cu` |
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| 8. |
An alkene given two moles of HCHO, one mole of `CO_2` and one mole of `CH_3COCHO` on ozonolysis. What is its structureA. `CH_2=C=CH-CH_2-CH_3`B. `CH_2=CH-oversetoverset(CH_3)|CH-CH=CH_3`C. `CH_2=C=undersetunderset(CH_3)|C-CH_3`D. `CH_2=C=oversetoverset(CH_3)|C-CH=CH_2` |
| Answer» Correct Answer - D | |
| 9. |
Hydrocarbon contianing following bond is most reactiveA. `C-=C`B. `C=C`C. `C-C`D. All of these |
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Answer» Correct Answer - A `-C-=C-` is most reactive of because of sp-hybridization |
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| 10. |
Heating of alkanes with fuming sulphuric acid or oleum at high temperature, which forms sulphonic acid, is calledA. NitrationB. HalogenationC. SulphonationD. Oxidation |
| Answer» Correct Answer - C | |
| 11. |
Sodium ethoxide is a specific reagent forA. DehydrationB. DehydrogenationC. DehydrohalogenationD. Dehalogenation |
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Answer» Correct Answer - C `CH_3-CH_2-CH_2-Brunderset"dehydrohalogenation"overset(C_2H_5ONa)toCH_3-CH=CH_2+HBr` |
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| 12. |
On mixing tetraethyl lead to gasoline available at petrol pumpsA. Calorific value of the fuel increasesB. Odour diminishesC. Less smoke is obtained on combustionD. Antiknock property of fuel increases |
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Answer» Correct Answer - D Anti-Knocking properties of fuel increases. |
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| 13. |
One mole of propanone and one mole of formaldehyde are the products of ozonolysis of one mole of an alkene. The alkene may beA. 2-methylpropeneB. 2,2-dimethyl-1-buteneC. PropeneD. 2-butene |
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Answer» Correct Answer - A `underset"2-methylprop ene"(CH_3-oversetoverset(CH_3)(|)C=CH_2)underset((ii)Zn//H_2O)overset((i)O_3//CH_2Cl_2, 196-200 K)to underset"proponone "(CH_3-oversetoverset(CH_3)(|)C=O)+underset"formaldehyde""HCHO"` |
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| 14. |
Which is the most reactive hydrocarbon in the followingA. EthaneB. EthyneC. EtheneD. Methane |
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Answer» Correct Answer - B Alkyne gt Alkene gt Alkane |
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| 15. |
In the preparation of alkanes, a concentrated aqueous solution of sodium or potassium salts of saturated carboxylic acid are subjected toA. HydrolysisB. OxidationC. HydrogenationD. Electrolysis |
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Answer» Correct Answer - B `2CH_3COONa+2H_2Ooverset"electrolysis"to CH_3-CH_3+2CO_2+2NaOH+H_2` |
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| 16. |
Gasoline has compositionA. `C_8 -C_12`B. `C_2-C_5`C. `C_6-C_8`D. None of these |
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Answer» Correct Answer - C The approximate composition of gasoline is `C_6 - C_8` at boiling point `70-120^@C` and is used in motor fuel, dry cleaning , petrol gas etc. |
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| 17. |
The olefin which on ozonolysis gives `CH_3CH_2CHO` and `CH_3CHO` isA. 1-buteneB. 2-buteneC. 1-penteneD. 2-pentene |
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Answer» Correct Answer - D `CH_3CH_2CH=CHCH_3 underset(Zn//H_2O)overset(O_3)to underset"Propanal"(CH_3CH_2CHO)+underset"Ethanal"(CHOCH_3)` |
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| 18. |
`CH_3CHO=CHCHO` is oxidized to `CH_3CH=CHCOOH` usingA. Alkaline potassium permanganateB. Acidified potassium permanganateC. Selenium dioxideD. Osmium tetroxide |
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Answer» Correct Answer - B `CH_3-CH=CH-CHOunderset"KMnO"overset"Acidic"to CH_3-CH=CH-COOH`. |
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| 19. |
Propene when heated with chlorine at about `500^@` C formsA. `CH_2Cl.CH=CH_2`B. `CH_3.CHCl.CH_2Cl`C. `CH_2Cl. CHCl. CH_2Cl`D. All of three |
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Answer» Correct Answer - A `CH_3-CH=CH_2+Cl_2overset(500^@C)to undersetunderset(Cl)(|)CH_2-CH=CH_2+HCl` This reaction is called allylic halogenation reaction because halogenation occurs at the allylic position of an alkene |
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| 20. |
When alcoholic solution of ethylene dibromide is heated with granulated zinc, the compound formed isA. EthyleneB. EthyneC. CyclobutaneD. Butane |
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Answer» Correct Answer - A `undersetunderset(Br)(|)CH_2-undersetunderset(Br)(|)CH_2+Zn to ZnBr_2 + CH_2 =CH_2` |
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| 21. |
A solution of (+) -2-chloro-2-phenylethane in toluene racemises slowly in the presence of small amount of `SbCl_5` , due to the formation ofA. CarbanionB. CarbeneC. Free-radicalD. Carbocation |
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Answer» Correct Answer - D `SbCl_5` is used for the formation of carbocation |
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| 22. |
A liquid hydrocarbon can be converted to gaseous hydrocarbon byA. CrackingB. HydrolysisC. OxidationD. Distillation under reduced pressure |
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Answer» Correct Answer - A `underset"Hexane Liquid"(C_6H_14)oversetDeltatounderset"Butane"(C_4H_10)+underset"Ethene Gas"(C_2H_2)` |
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| 23. |
Thermal decomposition of alkanes in the absence of air is called asA. CrackingB. OxidationC. CombustionD. Hydrogenation |
| Answer» Correct Answer - A | |
| 24. |
2-Methylbutane on reacting with bromine in the presence of sunlight gives mainlyA. 1-bromo-2-methylbutaneB. 2-bromo-2-methylbutaneC. 2-bromo-3-methylbutaneD. 1-bromo-3-methylbutane |
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Answer» Correct Answer - B `H_3C-undersetunderset(CH_3)(|)CH-CH_2-CH_3+Br_2to underset"Major"(H_3C -undersetunderset(CH_3)(|)oversetoverset(Br)(|)C-CH_2-CH_3)` |
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| 25. |
Statement 1: Friedel-Crafts reaction of benzene with n-propyl chloride gives isopropylbenzene. Statement 2:Benzene undergoes electrophile substitution readilyA. Statement 1 is true , statement 2 is true , statement 2 is a correct explanation for statement 1B. Statement 1 is true , statement 2 is true , statement 2 is not a correct explanation for statement 1C. Statement 1 is true , statement 2 is falseD. Statement 1 is false , statement 2 is true |
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Answer» Correct Answer - B The initially formed n-propyl cation first undergoes rearrangement by 1,2-hybride shift to form the more stable isopropyl cation which then attacks the benzene ring to form isopropylbenzene |
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| 26. |
An acyclic hydrocarbon P , having molecular formula `C_6H_10`, gave acetone as the only organic product through the following sequence of reaction, in which Q is an intermediate organic The structure of compound P isA. `CH_3CH_2CH_2CH_2-C-=C-H`B. `H_3CH_2C-C-=CH_2CH_3`C. D. |
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Answer» Correct Answer - D `underset"(P)"(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-C-=CH)overset(dil H_2SO_4//HgSO_4)to CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-oversetoverset(O)(||)C-CH_3 overset(NaBH_4//dil acid)to underset"(Q)"(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-undersetundersetH|overset"OH"|C-CH_3)underset((-H_2O))overset(conc.H_2SO_4)to CH_3-oversetoverset(CH_3)|C=undersetunderset(CH_3)|C-CH_3"(major)"overset(O_3//Zn//H_2O)to CH_3-overset(CH_3)overset|C=O` |
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| 27. |
The correct order of boiling points of 2, 2-dimethylpropane, 2 methylbutane and n pentane isA. n-pentane gt 2,2-dimethylpropane gt 2-methylbutaneB. n-pentane gt 2-methylbutane gt 2,2-dimethylpropaneC. 2,2-dimethylpropane gt 2-methylbutanegt n-pentaneD. 2-methylbutane gt n-pentane gt 2,2-dimethylpropane |
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Answer» Correct Answer - B Branching of the chain makes the molecule more compact the thereby decreases the surface area. The intermolecular forces which depend upon the surface area, become small in magnitude on account of branching. Consequently , the boiling points of branched chain alkanes are less than the straight chain isomers. |
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| 28. |
Assertion :Iodination of alkanes is reversible Reason:Iodination is carried out in presence of iodic acidA. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. if assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - B Iodination is reversible since formed HI is a strong reducing agent and reduces the alkyl iodide back to alkane. `CH_4+I_2 hArr CH_3I+HI` |
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| 29. |
`R-CH_2-C Cl_2-Roverset"Reagent"to R-C-=C-R` The reagent isA. NaB. HCl and `H_2O`C. KOH in `C_2H_5OH`D. Zn |
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Answer» Correct Answer - C `R-CH_2-C Cl_2-Roverset(KOH+C_2H_5OH)to R-C-=C-R+2HCl` This reaction is an example of dehydrohalogenation . Hence, alcoholic KOH is used as a reagent |
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| 30. |
The halogen which is most reactive in the halogenation of alkenes under sunlight isA. ChlorineB. BromineC. IodineD. All equal |
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Answer» Correct Answer - A `C_2H_4+Cl_2underset"hv"overset(C Cl_4)to underset"Ethelene Chloride"(Cl-CH_2-CH_2-Cl)` |
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| 31. |
Which of the following statements are correct during halogenation of alkaneA. The yield of the alkyl halide depends upon the bond dissociation energy of the type of C-H bondB. The yield of the alkane depends upon the number of a particular type of C-H availableC. The fluoro compounds cannot be prepared because of high bond energy of F-FD. Iodo compounds cannot be prepared by this method because the backward reaction is thermodynamically more favourable |
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Answer» Correct Answer - A::B::D During the halogenation of alkanes the yield depends upon (i) Bond dissociation energy of C-H bond. More easily the bond can be cleaved, greater will be the yield of the corresponding alkyl halide. (reativity factor). `rArr` Choice (a) is correct (ii)As a chemical reaction takes place due to the collision between the molecules or radicals, more is the possibility for a type of collision, more is the possiblity of the yield corresponding to alkyl halide. Hence, if a type of C-H bond is more in number then one can expect greater number of collision of `X^dot` with the C-H bond and hence greater will be the yield (number factor) `rArr` Choice (b) is correct. (iii)During the iodination of alkanes, `CH_4+I_2 to CH_3-I+HI` due to low bond energy of HI and C-I, so backward reaction is thermodynamically more favourable Hence , choice (d) is correct . (iv)During fluorination , H-F is formed , the bond energy of HF is so very high that the exothermicity lead to explosion that is why fluoro compounds are not prepared by this method . `rArr` Choice (c ) is incorrect. |
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| 32. |
On mixing an alkane with chlorine and irradiating with ultra violet light, it forms only one monochloro alkane. The alkane isA. PropaneB. PentaneC. Iso-pentaneD. Neo-pentane |
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Answer» Correct Answer - D In chlorination of alkanes, hydrogen is replaced by chlorine. In neo-pentane, only one type of hydrogen is present, hence replacement of any hydrogen atom will give the same product `H_3C-underset(CH_3)underset|oversetoverset(CH_3)(|)C-CH_3overset(Cl_2//UV)to H_3C-undersetunderset(CH_3)(|)oversetoverset(CH_2Cl)(|)C-CH_3` |
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| 33. |
Which of the following does not react with `PCI_5`A. `CH_3OH`B. `CH_3COOH`C. `CH_3CHO`D. `C_2H_6` |
| Answer» Correct Answer - D | |
| 34. |
Assertion:Propene reacts with HBr in presence of benzoyl peroxide to yield 2-bromopropane. Reason:In presence of peroxide , the addition of HBr to propene follows ionic mechanismA. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. if assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - D Propene reacts with HBr in presence of benzoyl peroxide to give 1-bromopropane. In presence of peroxide , the addition of HBr to propane occurs by free radical mechanism. |
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| 35. |
Propene, `CH_(3)-CH = CH_(2)`, can be converted to `1`-propanol by oxidation. Which set of reagents among the following is ideal to effect the conversion?A. `KMnO_(4)("alkaline")`B. Osmium tetraoxide `(OsO_(4)//CH_(2)Cl_(2))`C. `B_(2)H_(5)` and alk. `H_(2)O_(2)`D. `O_(3)//Zn` |
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Answer» Correct Answer - 3 `KMnO_(4)(`alkaline) and `OsO_(4)//CH_(2)Cl_(2)` are used for hydroxylation of double bond while `O_(3)//Zn` is used for ozonolysis. Therefore , the right option is `(3) i.e.` `3CH_(3)-CH=CH_(2)overset(B_(2)H_(6))rarr(CH_(3)CH_(2)CH_(2))Boverset(H_(2)O_(2)//NaOH)rarrunderset(1-"propanol")(3CH_(3)CH_(2)CH_(2)-OH)` |
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| 36. |
Which compound will yield 2-methyl-6-oxoheptanal upon treatment with ozone followed by `Zn//H_(2)O`?A. B. C. D. |
| Answer» Correct Answer - C | |
| 37. |
Reaction of 1,1-dibromopentane with three equivalents of `NaNH_(2)` in ether is followed by treatment with `0.1 M HCl " at " 0^(@) C.` What is the preduct?A. CyclopenteneB. 1,2-pentadieneC. 2-pentyneD. 1-pentyne |
| Answer» Correct Answer - D | |
| 38. |
Ethene gives with acidic `KMnO_4` solutionA. Ethylene glycolB. Ethylene oxideC. FormaldehydeD. Acetaldehyde |
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Answer» Correct Answer - C `CH_2=CH_2+2[O]overset(KMnO_4)tounderset"Formaldehyde""HCHO+HCHO"` |
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| 39. |
In a reaction, if half of the double bond is broken and two new bonds are formed, this is a case ofA. EliminationB. AdditionC. DisplacementD. Rearrangement |
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Answer» Correct Answer - B e.g. `CH_2=CH_2+Br_2 to undersetunderset(Br)(|)CH_2-undersetunderset(Br)(|)CH_2` Half of the double bond is broken. Its means `pi` bond is broken while sigma bond is retained also two new C-Br bonds are formed |
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| 40. |
Ethene when treated with `Br_2` in the presence of `C Cl_4` which compund is formedA. 1,2-dibromoethaneB. 1-bromo-2-chloroethaneC. Both (a) and (b)D. 1,1,1-tribromoethane |
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Answer» Correct Answer - A `CH_2=CH_2+Br_2 overset(C Cl_4)to underset"1,2-dibromo ethane"(undersetunderset(Br)(|)CH_2-undersetunderset(Br)(|)CH_2)` |
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| 41. |
Conjugate double bond is present inA. PropyleneB. ButadieneC. IsobutyleneD. Butylene |
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Answer» Correct Answer - B Butadiene `CH_2=CH-CH-CH_2` Double bonds separated by a single bond is known as conjugated double bond. |
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| 42. |
Which of the following statement is/are correct about benzeneA. It burns with scooty flameB. It undergoes electrophilic substitution reactionC. Its resonace energy is `36 kcal mol^(-1)`D. It is highly unsaturated and decolourises bromine water |
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Answer» Correct Answer - A::B::C (a),(b) and (c ) are correct statements. (d) is wrong due to delocalization of `pi`-electrons |
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| 43. |
Position of double bond in an organic compound is determined byA. OzonolysisB. OxidationC. ReductionD. Hydrogenation |
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Answer» Correct Answer - A Ozonolysis is useful in locating the position of a double bond in an alkene. The double bond is obtained by joining the carbon atoms of the two carbonyl compounds. For example let the product of ozonolysis be two molecules of ethanal . `CH_3-overset(H)overset(|)C=O+O=oversetoverset(H)(|)C-CH_3 to CH_3 -underset"2-Butene"(CH=CH)-CH_3` |
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| 44. |
A reagent used to test for unsaturation of alkene isA. Conc. `H_2SO_4`B. Ammoniacal `Cu_2Cl_2`C. Ammoniacal `AgNO_3`D. Solution of `Br_2` in `C Cl_4` |
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Answer» Correct Answer - D Solution of bromine in carbon tetrachloride is used to test for unsaturation of alkene. Red colour of bromine disappears due to the formation of colourless dibromo ethane `(C_2H_4Br_2)` |
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| 45. |
The test for unsaturation is confirmed by the decolourisation of which of the followingA. iodine waterB. `CuSO_4` solutionC. Bromine waterD. All of these |
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Answer» Correct Answer - C By adding bromine water to a solution, if the colour of bromine water decolourise then the compound is unsaturated . This is a confirmatory test for unsaturation. |
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| 46. |
Statement 1:1-Butene on reaction with HBr in the presence of a peroxide produces 1-bromo-butane Statement 2:It involves the free radical mechanismA. Statement 1 is true , statement 2 is true , statement 2 is a correct explanation for statement 1B. Statement 1 is true , statement 2 is true , statement 2 is not a correct explanation for statement 1C. Statement 1 is true , statement 2 is falseD. Statement 1 is false , statement 2 is true |
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Answer» Correct Answer - A `underset"1-Butene"(CH_3-CH_2-CH=CH_2+Br_2)to underset"1,2-dibromobutane"(CH_2-underset"Br"underset"|"oversetoversetH|(C^dot)-CH_2Br)` |
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| 47. |
1-Butene may be converted to butane by reaction withA. Zn-HClB. Sn-HClC. Zn-HgD. `Pb//H_2` |
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Answer» Correct Answer - D Pd acts as catalyst |
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| 48. |
n-pentane and isopentane can be distinguished byA. `Br_2`B. `O_3`C. Conc. `H_2SO_4`D. `KMnO_4` |
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Answer» Correct Answer - D On oxidation, with `KMnO_4` , they give different alcohols `underset"n-pentane"(CH_3CH_2CH_2CH_2CH_3)underset([O])overset(KMnO_4)to underset(1^@"alcohol")(CH_3CH_2CH_2CH_2CH_2OH)` `CH_3CH_2-underset(CH_3)underset(|)CH-CH_3underset"[O]"overset(KMnO_4)to underset(3^@"alcohol")(CH_3CH_2-undersetunderset(CH_3)(|)oversetoverset(OH)(|)C-CH_3)` |
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| 49. |
Propyne and propene can be distinguished byA. Conc. `H_2SO_4`B. `Br_2` in `C Cl_4`C. Alk. `KMnO_4`D. `AgNO_3` in `NH_3` |
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Answer» Correct Answer - D Propene and propyne, both are unsaturated hence give positive test with conc. `H_2SO_4, Br_2//C Cl_4` and alk. `KMnO_4` (addition reaction ) . With ammonical `AgNO_3` , only terminal alkynes (like acetylene, propyne etc.) react. Alkenes do not react with this reagent. The reason is that alkynes have acidic hydrogen. `CH_3C-=CH+AgNO_3 + 2NH_4OH to 2CH_3 - C-=C` `Ag darr + 2NH_4 +2H_2O` |
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| 50. |
But-1-yne and But-2-yne can be distinguished by :A. `Br_(2)//C Cl_(4)`B. `KMnO_(4)//overset(Theta)(O)H aq.("cold")`C. `(AgNO_(3)+NH_(4)OH)`D. All |
| Answer» Correct Answer - C | |