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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. |
(addition product) Sum of x and y is _______. |
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Answer» Correct Answer - 8 |
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| 2. |
Ethylene reacts with `Br_(2)` to give `1,2`-dibromoethane. The reaction proceeds through the formation of the intermediateA. `BrCH_(2)overset(+)(CH_(2))`B. `BrCH=overset(+)(CH)`C. D. |
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Answer» Correct Answer - C The first step is also formation of cyclic bromonium ion (a bridged or nonclassical carbonium ion), followed by an attack by the bromide ion. |
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| 3. |
The bond dissociation of `C=C` in ethene isA. `63 kcal mol^(-1)`B. `146 kcal mol^(-1)`C. `88 kcal mol^(-1)`D. `95 kcal mol^(-1)` |
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Answer» Correct Answer - B The `C=C` bond of ethene has the greater bond dissociation energy `(146 kcal mol^(-))` compared to the `C-C` bond of ethane `(88 kcal mol^(-1))` because with `C=C`, two bonds are broken and with `CoC`, only one. In spite of the greater bond dissociation energy of the double bond, alkenes are more reactive than alkanes beacuse in most reactions, only `pi` bond is broken. Its bond dissociation energy of `51 kcal mol^(-1)` is less than bond dissociation energy of `C-C sigma` bond of ethane. |
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| 4. |
S-I: Acidic character of ethane, ethene and ethyne are in the order `CH-=CH gt CH_(2)=CH_(2) gt CH_(3)-CH_(3)` S-II: Higher the s-character in hybridization of carbon atom, more is the acidic nature of H atom joined to it.A. S-I & II are correct, S-II is correct explanation of S-IB. S-I&II are correct, S-II is not correct explanation of S-IC. S-I is true, but S-II is false.D. S-I is false, ut S-II is true |
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Answer» Correct Answer - A |
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| 5. |
Polythene is obtained by the polymerization ofA. StyreneB. A mixture of ethylene and styreneC. AcetyleneD. Ethene |
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Answer» Correct Answer - D |
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| 6. |
In the following reaction, A and B respectively. are, `Aoverset(HBr)toC_(2)H_(5)Broverset(B)toA`A. `C_(2)H_(4)`& alcoholic `KOH//Delta`B. `C_(2)H_(4)Cl&` aqueous `KOH//Delta`C. `C_(2)H_(5)OH` and aq `KOH//Delta`D. `C_(2)H_(2)&Br_(2)` |
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Answer» Correct Answer - A |
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| 7. |
In the reaction `(CH_(3))_(2)CH-underset(CH_(3))underset(|)(CH)-overset(+)S(CH_(3))_(2)Broverset(Heat)rarr` Which of the following alkenes is formed in the largest amount ?A. `(CH_(3))_(2)C=CHCH_(3)`B. `CH_(2)=overset(CH_(3))overset(|)C-CH_(2)CH_(3)`C. `(CH_(3))_(2)CHCH=CH_(2)`D. No alkene formation |
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Answer» Correct Answer - C Sulphonum salts undergo elimination in accordance with the `Hofmann rule which says that the predominant alkene is the least substituted alkene. |
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| 8. |
Dehydrohalogenation of ethyl chloride in presence of alc. KOH produces the followingA. `HC-=CH+KCl+H_(2)O`B. `CH_(4)+KCl+H_(2)O`C. `CH_(2)=CH_(2)+KCl+H_(2)O`D. `C_(2)H_(4)+HCl` |
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Answer» Correct Answer - C |
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| 9. |
The peroxide effect involvesA. Ionic mechanismB. Free-radical mechanismC. Heterolytic fission of double bondD. all the above |
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Answer» Correct Answer - B |
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| 10. |
Ozonolysis reaction is useful in detecting theA. Presence of carboxyl functional groupB. Presence of carboxylic functional groupC. Position of double bonds in alkenesD. All the above |
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Answer» Correct Answer - C |
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| 11. |
Acidic potessium dichromate oxidises 2-Butene toA. butan-2-oneB. Ethanoic acid+`CO_(2)`C. Butanoic acidD. Ethanoic acid only |
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Answer» Correct Answer - D |
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| 12. |
When isopropyl iodide is treated with a hot concentrated alcoholic solution of a strong base like potassium hydroxide, is obtained.A. PropyleneB. potassium bromideC. waterD. all of these |
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Answer» Correct Answer - D `CH_(3)underset(I)underset(|)CHCH_(3)+KOHunderset(Heat)overset(C_(2)H_(5)OH)rarrCH_(3)CH=underset("Propylene")(CH_(2))+KBr+H_(2)O` |
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| 13. |
Which of the following compounds are used to synthesize alkenes through the Wittig reaction?A. AldehydesB. KetonesC. Both (1) and (2)D. Carboxylic acids |
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Answer» Correct Answer - C Direct conversion of `C=O` of aldehydes and ketones into `C=C` using a phosphorane or phosphorus ylide is called a Writing reaction. |
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| 14. |
Product (C) of reaction isA. B. C. D. |
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Answer» Correct Answer - C |
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| 15. |
Which of the following shows geometrical isomerism.A. `BrCH=C=C=CHBr`B. C. `CH=C=C=C" "Br_(2)`D. `CH_(2)+C=C=CHBr` |
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Answer» Correct Answer - A |
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| 16. |
The alkene that exhibits geometrical isomerism isA. PropeneB. 2-meethyl propeneC. 2-buteneD. 2-methyl-2-butene |
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Answer» Correct Answer - C |
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| 17. |
How many different products (exluding stereosiomer) can be obtained by following reaction |
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Answer» Correct Answer - 4 |
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| 18. |
Examine the structural formulas of following compounds and find how many compounds will produce. |
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Answer» Correct Answer - 5 |
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| 19. |
The total number of alkenes possible by dehydrobromination of 3-bromo-3-cyclopentylhexane using alcoholic `KOH` is |
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Answer» Correct Answer - 5 |
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| 20. |
When ethanol vapours are passed over alumina heated at `350^(@)C` the main product obtained isA. `C_(2)H_(6)`B. `C_(2)H_(4)`C. `C_(2)H_(2)`D. `C_(2)H_(5)OC_(2)H_(5)` |
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Answer» Correct Answer - B |
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| 21. |
Dehydrtion of alcohol is unimolecular as well as bimolecular reaction. Dehydration takes place by the use of non volatile acids. The reaction is maily used for the preparation of alkenes. Alkenes can also be prepared by dehalogenation of vic dihalides and dehydro halogenation. Q. In the given reaction, the final product is/are: `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH_(2)-CH_(2)-CH_(2)OHunderset(Delta)overset(H_(2)SO_(4))to`A. Only `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH=CH_(2)`B. Only `CH_(3)-underset(CH_(3))underset(|)(C)=underset(CH_(3))underset(|)(C)-CH_(3)`C. `CH_(3)-=underset(CH_(3))underset(|)(C)-CH_(2)-CH_(2)-CH_(3)`D. Mixture of a and b |
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Answer» Correct Answer - D |
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| 22. |
Dehydrtion of alcohol is unimolecular as well as bimolecular reaction. Dehydration takes place by the use of non volatile acids. The reaction is maily used for the preparation of alkenes. Alkenes can also be prepared by dehalogenation of vic dihalides and dehydro halogenation. Q. Major product of the reaction isA. B. C. D. |
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Answer» Correct Answer - C |
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| 23. |
Match the reagent from Column I which on reaction with `CH_(3)-CH=CH_(2)` gives some product given in Column II as per the codes given below |
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Answer» Correct Answer - B |
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| 24. |
The molecules having dipole moment are :A. 2,2-DimethylpropaneB. trans-pent-2-eneC. cis-Hex-3-eneD. 2,2,3,3-Tetramethybutane |
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Answer» Correct Answer - B::C |
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| 25. |
Which among the following alkenes will be most reaction during hydrogenation reaction.A. `CH_(3)-CH=CH_(2)`B. C. `H_(2)C=CH_(2)`D. |
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Answer» Correct Answer - C |
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| 26. |
Assertion(A): When is subjected to dehydrohalogenation using NaOEt/EtOH, the product contains no deuterium . Reason(R): `E_(2)` follows anti elimination.A. If both A and R are true and R is the correct explanation of A.B. If both A and R are true and R is not the correct explanatio of A.C. If A is true but R is falseD. If A is false and R is true. |
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Answer» Correct Answer - A |
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| 27. |
Identify the molecule having `sp^(2)` hybridised carbons onlyA. 1-penteneB. 2-butaneC. buta-1,3 dieneD. propane |
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Answer» Correct Answer - C |
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| 28. |
Alkenes are only very slightly soluble inA. chloroformB. etherC. waterD. benzene |
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Answer» Correct Answer - C Being relatively nonpolar themselves, alkenes disolvents or solvents of low polarity. |
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| 29. |
Unbranched alkenes containing `5` to …… `C` atoms are liquids at room temperature.A. `18`B. `17`C. `16`D. `15` |
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Answer» Correct Answer - B Eighteen onwards are solids at room temperature. |
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| 30. |
Alkenes are readily hydrogenated under pressure in the presence of a catalyst. Which of the following catalysts is effective at room temperature ?A. Platinum blackB. Palladium blackC. Raney nickelD. Alll of these |
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Answer» Correct Answer - D All are effective at room temperature. Platinum and palladium black are the respective metals in a very finely divided state. They are usually prepared by reducing their soluble salts with formaldehyde. |
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| 31. |
Which of the following reagents is required in the synthesis of alkenes by Witting reaction?A. `H_(2)N NH_(2)`B. `B_(2)H_(6)`C. `(C_(6)H_(5))_(3)P`D. `(C_(2)H_(5)O)_(3)P` |
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Answer» Correct Answer - C Triphenylphosphine, `(C_(6)H_(5))_(3)P`, is the starting point. It is used to synthesize phosphorus ylides. |
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| 32. |
The stereospecificity of the reactions is a very good evidence that E2 reactions proceed through an anti-periplanar transition state. More evidence comes from the reactions of substituted cyclohexanes. Generally, all cyclohexanes are most stable in chair conformations. we know that substituets on cyclohexanes can be parallel with one another only if they are both axial. an equatorial C-X bond is anti-periplanar only to C-C bonds and cannot take part in an elimination. for unsubstitueted cyclohexyl halides treated with base, this is not a problem because, although the axial conformer is less stable, there is still a significant amount present and elimination can take place from thi conformer Q. Let us consider the two-diastereoisomeric cyclohexyl chlorides derived from menthol which react under same coditions with sodium ethoxide. Find the correct one:A. Diastereomer A will react fasterB. Diastereomer B will react fasterC. Diastereomer A will give two productD. Both A and C are correct |
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Answer» Correct Answer - D |
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| 33. |
Products are.A. B. C. D. |
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Answer» Correct Answer - A::B::C::D |
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| 34. |
Which of the following products are formed in the reaction? A. B. C. D. |
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Answer» Correct Answer - C::D |
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| 35. |
The major product isA. B. `Ph-C=C-Ph`C. `Ph-C-=CH`D. `Ph-CH=CH_(2)` |
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Answer» Correct Answer - B |
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| 36. |
Which of the follwing alkenes was called olefiant gas?A. `CH_(2)`B. `C_(2)H_(4)`C. `C_(3)H_(6)`D. `C_(4)H_(8)` |
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Answer» Correct Answer - B Unlike alkanes that can have a member with a single `C` atoms `(CH_(4))`, the simplest alkene must have two carbons: `H_(2)C=CH_(2)` (ethene or ethylene). An old name of alkenes that is still often used is the name olefins. Ethene (ethylene), the simplest olefin (alkene), was called oldfiant gas (Latin: oleum, oil+facere, to make) beacuse ethene `(C_(2)H_(4))` reacts with chlorine or bromide to form a liquid (oil). |
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| 37. |
Which of the follwing undergoes fastest dehydrohalogention ?A. `CT_(3)CH_(2)I`B. `CD_(3)CH_(2)I`C. `CH_(3)CH_(2)I`D. All are equally reactive |
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Answer» Correct Answer - C `E2` elimination shows a large hydrogen isotope effect. The heavier the isotope, the slower the reaction. Therefore, the order of decreasing reactivity is `3 gt 2gt 1`. |
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| 38. |
Match the column |
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Answer» Correct Answer - A::B::C::D |
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| 39. |
Match the column (I) and (II) |
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Answer» Correct Answer - A::B::C::D |
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| 40. |
Which of the following statements is incorrect ?A. The `C-H` bond length in both ethene and ethane is identical.B. The `C-H` bond in ethane is longer than in ethene.C. The `C-H` bond in ethene is shorter than in ethane.D. Both (2) and (3) |
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Answer» Correct Answer - C The `C-H` bond in ethane is shorter and stronger than in ethane because it is formed by the overlap of `sp^(3)` hybrid orbital `(HO)` of `C`, instead of `sp^(3)HO` as in ethane. Compared with an `sp^(3)HO`, and `sp^(2)HO` has less `p` character and more `s` character. A `p` orbital extends some distance form the nucleus while an `s` orbital lies close about the nucleus. Thus, as the `s` character of a hybrid orbital increases, the effective size of the hybrid orbital decreases resulting in corresponding decrease in the length of the bond to a given second atom. Thus, an `sp^(2)-s-C-H` bond is shorter than an `sp^(3)-sC-H` bond. The `C-H` bond length is `1.09Å` in ethene compared with `1.112 Å` in ethane. Simililarly, the carbon-carbon bond distance in propylene `(1.501Å)` is shorter in comparison with the carbon-carbon bond distance in ethane `(1.534Å)` beacuse an `sp^(2)-sp^(3)` bond has more `s` character than an `sp^(3)-sp^(3)` bond, Since shorter bond are stronger bonds, the `C-H` bond dissociation energy in ethylene `(108 Kcal)` is larger than energy in propylene `(92Kcal)`, and the `C-C` bond dissociation enrgy in propylene `(92 Kcal)` is greater than that in ethane `(88 Kcal)` |
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| 41. |
In `Coverset(a)-C=Coverset(b)-C=Coverset(c )-Coverset(d)-C` the strongest `C-C` single bond isA. bB. aC. cD. d |
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Answer» Correct Answer - A It is formed form the overlap of two `sp^(2)` hybrid orbitals. (a) and (c ) are `sp^(3)-sp^(2)` bond, and (d) is `sp^(3)-sp^(3)` bond. In general, an orbital with more `s` character forms stronger and shorter bond because the more the `s` character, the more is the probability of finding the shared `e^(-)s` closer to the positively charged nuclei and, hence, the stronger is the attraction. |
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| 42. |
Identify the correct match from the following lists A. I-B,II-d,II-eB. I-b,II-c,III-eC. I-d,II-a,III-eD. I-e,II-c,III-e |
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Answer» Correct Answer - B |
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| 43. |
Which of the following will produce Allyl halide?A. `CH_(2)=CH-CH_(3)+SO_(2)Cl_(2)underset("traces of peroxide")overset(475K)to`B. `CH_(2)=CH-CH_(3)+Cl_(2)overset(400^(@)C-500^(@)C)to`C. `CH_(2)=CH-CH_(3)overset(NBS)to`D. All the above |
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Answer» Correct Answer - D |
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| 44. |
Which one of the following compounds will give in the presence of peroxide a product different from that obtainded in the absence peroxide ?A. 1-buteneB. 2-butene, HClC. 1-butene, HBrD. 2-butene,HBr |
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Answer» Correct Answer - C |
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| 45. |
Alkenes mainly undergoA. electrophilic addition reactionsB. nucleophile addition reactionsC. free-radical addition reactionsD. both and (1) and (3) |
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Answer» Correct Answer - A Because the `pi` bond results from overlapping `p` orbitals, the `pi` electrons lie above and below the plane of the double bond. Therefore, the electrons of the `pi` bonds are exposed and susceptible to electron-seeking reagents called electrophiles. Electrophiles include positive reagents such as protons `(H^(+))`, neutral reagents such as bromine ( beacuse it can be polarized so that one end is positive), and the Lewis acids such as `AlCl_(3)` and `BF_(3)`. Metal ions containing vacent orbitals such as silver as silver ion `(Ag^(+))`, mercuric ion `(Hg^(2+))`, and platinum ion `(Pt^(2))` also act as electrophiles. |
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| 46. |
Which of the compounds is the least reactive toward the addition of hydrogen halides?A. `(CH_(3))_(2)C=CH_(2)`B. `CH_(3)CH=CHCH_(3)`C. `CH_(2)=CH-Cl`D. `CH_(2)=CH_(2)` |
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Answer» Correct Answer - C During the addition of acids such as `HX`, the rate controlling step is the formation of carbocation. Therefore, the more stable the carbonation, the faster is the reaction. As substituents, halogens tend to attract electrons. Just as electron release by alkyl groups disperses the positive charge and stabilizes a carbonation, electron withdrawal by halgoen intensifies the positive charge and destabilizes the carbonation. |
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| 47. |
Ethylene gives epoxy ethane on oxidation withA. `KMnO_(4)//OH^(-)`B. `K_(2)Cr_(2)O_(7)//H^(+)`C. `Ag_(2)O //200^(@)C`D. `H_(2)SO_(4)//170^(@)C` |
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Answer» Correct Answer - C |
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| 48. |
In one industrial synthesis of ethanol, ethane is first dissolved in `95%` sulphuric acid. In the second step, water is added and the mixture is heated. Outline the reaction involved. Strategy: Alkyl hydrogen sulphates are easily hydrolyzed to alcohols by heating with water. |
| Answer» `CH_(2)=CH_(2)underset(H_(2)SO_(4))overset(95%)rarrunderset("Ethyl hydrogen suphate")(CH_(3)CH_(2)OSO_(2)OH)underset(Delta)overset(H_(2)0)rarrCH_(3)CH_(2)OH+H_(2)SO_(4)` | |
| 49. |
In dehydrohalgenation by ethanolic `KOH`, the active base isA. ethanolB. `KOH`C. ethoxide ionD. hydroxide ion |
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Answer» Correct Answer - C `OH^(-)+C_(2)H_(5)OHoverset(rarr)larrC_(2)H_(5)O^(-)+H_(2)O` Ethoxide ion is a stronger base tan hydroxide ion. |
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| 50. |
Alkenes react rapidly with chlorine or bromine in non-nucleophilic solvents to formA. geminal dihalidesB. `alpha, omega`-dihalidesC. vicinal dihalidesD. a mixture of (1) and (3) |
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Answer» Correct Answer - C `CH_(2)=CH_(2) + Br_(2) rarr Br_(2)CH_(2)CH_(2)Br` |
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