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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. |
Which salt of carboxylic acid will be required to prepare ethane by sodalime decarboxylation? Give equation for the reaction. |
| Answer» `CH_(3)CH_(2)COO Na^(+)+NaOHunderset(Delta)overset(CaO)rarrCH_(3)-CH_(3)+Na_(2)CO_(3)` | |
| 2. |
In order to get propane gas, which of the following should be subjected to sodalime decarboxylation?A. Sodium butyrateB. Sodium propionateC. Mixtures of sodium acetate and sodiumethanoateD. Sodium formate |
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Answer» Correct Answer - B `C_(3)H_(7)COONa_NaOH overset(CaO)to C_(3)H_(8)+Na_(2)CO_(3) ` |
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| 3. |
A sample of petrol is a mixture of `30% n-` heptane and `70%` iso`-` octane . The sample has octane numberA. 70B. 30C. 15D. 35 |
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Answer» Correct Answer - a Petrol sample `30% n-`heptane `+70%` iso`-`octane since iso`-` octane is `70%` . Hence, octane no. is `70`. |
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| 4. |
Which of the following will have zero dipole moment ?A. `1,1-`DichloretheneB. `cis-1,2`DichloroetheneC. `trans -1,2-`DichloroetheneD. All have equal dipole moment |
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Answer» Correct Answer - c Dipole moment is a vector quantity. In trans`1,2-`dichloroethene, all the vectors cancel each other. |
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| 5. |
Which one is incorrect name ?A. PropyneB. But-2-yneC. Pent-3-yneD. But-1-yne |
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Answer» Correct Answer - C `overset1CH_3-overset2C-=overset3C-overset4CH_2overset5CH_3` It is 2-pentyne and not. 3-pentyne. |
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| 6. |
Acetylene is liberated by the electrolysis or an aqueous solution of:A. sodium acetateB. sodium succinateC. Sodium benzoateD. sodium fumarate. |
| Answer» Correct Answer - D | |
| 7. |
Predict wrong option for stabilityA. `2,3-`Dimetylbut`-2-`ene`gt2-`Methylpent`-2-`eneB. trans`-`Hex`-3-`ene`gtcis-`Hex`-3-`eneC. cis`-`Hex`-3-`ene`gt` Hex `-1-`eneD. trans`-`Hex `-2-`ene`gt2-`Methylpent`-2-`ene |
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Answer» Correct Answer - d Stability depends on hyperconjugation which further depends on total number of `alphaH`. |
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| 8. |
Which of the following is not an isomer of 3-methylbut-1-yne ?A. Pent-1-yneB. Buta-1,3-dieneC. Pent-2-yneD. Penta-1,3-diene |
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Answer» Correct Answer - B 1,3-Butadiene `(CH_2=CHCH=CH_2)` has only four carbon atoms while all others have five carbon atoms. |
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| 9. |
The electrophile, `E^(+)` attacks the benzene ring to generate the intermediate `sigma`-complex. Which `sigma`-complex is of lowest energy?A. B. C. D. |
| Answer» Correct Answer - D | |
| 10. |
Friedel-Crafts alkylation is expected to proceed through carbocationic intermediate. What would be the alkylation products when Benzene reacts with cyclopropyl chloride under the presence of anhydrous `AlCl_(3)`?A. B. C. D. |
| Answer» Correct Answer - B::D | |
| 11. |
Assertion `:` Alkyl benzene is not prepared by Friedel`-` Crafts alkylation of benzene. Reason `:` Alkyl halides are more reactive than acyl halides.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - B Mono alkyl benzene further undergoes acylation. |
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| 12. |
Liquid hydrocarbons can be converted to a mixture of gaseous hydrocarbons byA. hydolysisB. oxidationC. crackingD. distillation under reduced pressure |
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Answer» Correct Answer - C Cracking converts liquid hydrocarbons to gaseous hydrocarbons by cleavage of C-C and C-H bonds. |
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| 13. |
Assertion`:` Friedel`-`Crafts reaction is used to introduce an alkyl or acyl group in benzene nucleus Reason`:` Benzene is a solvent for the Friedel`-`Crafts alkylation of bromobenzene.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - c Yes, we use Fredel`-` Crafts reaction for introducing an alkyl or acyl group in benzene nucleus. Thus, assertion is true. However, the reason is not true because if benzene is used as a solvent, during alkylation of bromobenzene, benzene will be alkylated in preference to bromobenzene because benzene is more reactive for `SE` than bromobenzene. |
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| 14. |
Pick out the correct statement from the following and choose the correct answer from the codes given below (1) Hex-1,5-diene is a conjugated dience (2) Prop-1,2-diene is a conjugated dience (3) Hexa-1,3-diene is a conjugated dience (4) Buta-1,3, diene is an isolated dience (5) Prop-1,2-diene is a cummulative dieneA. 1,2B. 2,3C. 4,5D. 3,5 |
| Answer» Correct Answer - E | |
| 15. |
Alkenes are insoluble in ………… (A) benzene(B) water (C) ether (D) chloroform |
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Answer» Correct option is: (B) water As we know, "Like dissolve Like" benzene, ether and chloroform are non-polar in solvent while water is polar solvent. Alkene is also non-polar. Therefore, Alkene does not dissolve in water. Correct option is (B) water |
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| 16. |
How does the chain termination occurs in the halogenation reaction of alkanes? |
| Answer» Free radical terminates the chain reaction in the halogenation reaction by combining either by the same free radical or by different free radical. | |
| 17. |
Choose the comound which can react with `[Ag(NH_(3)))(2)]^(+)` and on treatment with alkaline `KMnO_(4)` gives `(CH_(3))_(3)C-O OH`A. `CH_(3)CH_(2)CH_(2)C=C-CH_(3)`B. `(CH_(3))_(2)CHCH_(2)C-=CH`C. `(CH_(3))_(3)C-C-=CH`D. `(CH_(3))_(3)C-C-=C-CH_(3)` |
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Answer» Correct Answer - C Because the compound reacts with `[Ag(NH_(3))_(2)]^(+)` it must have=CH group. Further as it gives `(CH_(3))_(3)C-COOH` with alkaline `KMnO_(4)` it should have `(CH_(3))_(3)C-C`= group. Therefore the compound is as shown in (C ) `(CH_(3))_(3)C--=CH overset(Alk.KMnO_(4))to (CH_(3))_(3)C-COOH+CO_(2)+H_(2)O` |
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| 18. |
Alkenes can be obtained from which industrial sources? |
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Answer» 1. The most important alkenes for chemical industry are ethene, propene and buta-1,3-diene. 2. Alkenes containing up to four carbon atoms can be obtained in pure form from the petroleum products. 3. Ethene is produced from natural gas and crude oil by cracking. |
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| 19. |
Arrange following hydrocarbons in the increasing order of acidic character: propane, propyne, propene. |
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Answer» Propyne > propene > propane |
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| 20. |
What will be product in the following reaction `CH_(3)-CH_(2)-CH_(2)-CH_(3)overset(KMnO_(4))rarr`? |
| Answer» No reaction will take place as alkanes except those having tertiary hydrogen resist oxidation. | |
| 21. |
Which of the following compounds will show geometrical isomerism?(i) H2C = CBr2(ii) (H3C)2C = CHCH3(iii) C6H5CH = CHCH3(iv) H3C - CH = CCI(CH3)(v) |
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Answer» Compounds (III), (IV) and (V) will show geometrical isomerism as they have each of the doubly bonded carbon atoms in their structures, attached to different atoms/groups of atoms. |
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| 22. |
How can propane be oxidized to propionic acid? |
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Answer» Propane undergoes oxidation to propionic acid in presence of mangenese stearate. `2CH_(3)CH_(2)CH_(3)+3O_(2)overset((CH_(3)COO)_(2)Mn)rarr2CH_(3)CH_(2)COOH+2H_(2)O` |
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| 23. |
What is the number of sigma `(sigma)` bonds and pi `(pi)` bonds in 4-Ethyl-2-,5,7-decatriene? |
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Answer» Number of sigma `(sigma)` bonds=31 Number of pi `(pi)` bonds=3 |
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| 24. |
The correct statement regarding the comparison of staggered and eclipsed conformations of ethane is ………..(a) the eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain. (b) the staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has no torsional strain. (c) the staggered conformation of ethane is less stable than eclipsed conformation, because staggered conformation has torsional strain. (d) the staggered conformation of ethane is less stable than eclipsed conformation, because staggered conformation has no torsional strain. |
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Answer» (b) the staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has no torsional strain. |
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| 25. |
What is the energy difference between the staggered and eclipsed conformations of ethane? |
| Answer» 12.5 kJ `"mol"^(-1)` | |
| 26. |
With respect to the conformers of ethane, which of the following statements is true ?A. Bond angle changes but bond length remains sameB. Both bond angle and bond length changeC. Both bond angles and bond length remains sameD. Bond angles remains same but bond length changes |
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Answer» Correct Answer - C In conformation bond angle and bond length remain same. There is only difference in spatial arrangement. |
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| 27. |
With respect to the conformers of ethane, which of the following statements is true ?A. Bond angle changes but bond length remains sameB. Both bond angle and bond length changeC. Both bond angle and bond length remain sameD. Bond angle remains same but bond length changes |
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Answer» Correct Answer - C Bond bond angle and bond length remains the same. Only dihedral angle and distances between the non-bonded hydrogen atoms change. |
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| 28. |
Statement-1. The guache conformation of ethylene glycol is more stable than its anti conformation Statement-2. The gauche conformation is stabilized by H-bonding.A. 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 |
| Answer» Correct Answer - A | |
| 29. |
Assertion. Benzene does not decolourize `Br_2`- water Reason. Benzene is stabilized by resonance due to delocalization of `pi`-electrons.A. If both assertion and reason are true, and reason is the true explanation of the assertion.B. If both assertion and reason are true, but reason is not the true explanation of the assertion.C. If assertion is true, but reason is false.D. If both assertion and reason are false |
| Answer» Correct Answer - A | |
| 30. |
Assertion`:` `C_(6)H_(6)` does not decolourize `Br_(2)` water. Reason`:` All the six carbon atoms have delocalized `pi-`electrons.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - a `C_(6)H_(6)` does not decolourise `Br_(20` water because of resonance stabilization due to delocalization of `pi-` electrons. |
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| 31. |
State Saytzeff rule. |
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Answer» In dehydrohalogenation the preferred product is the alkene that has the greater number of alkyl groups attached to doubly bonded carbon atoms. |
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| 32. |
The number of types of bonds between two carbon atoms in calcium carbide isA. one sigma , two piB. one sigma, one piC. two sigma , one piD. two sigma, two pi |
| Answer» Correct Answer - A | |
| 33. |
Which of the following carbide can be used to prepare methane by its action with water?A. Calcium carbideB. Silicon carbideC. Aluminium carbideD. Beryllium carbide |
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Answer» Correct Answer - C,D `(#DIN_OBJ_CHM_V02_C5_3_E01_405_S01.png" width="80%"> |
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| 34. |
An alkyl halide by formation of its Grignard reagent and heating with water gives propane. What is the original alkyl halide ?A. methyl iodideB. ethyl iodideC. ethyl bromideD. propyl bromide |
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Answer» Correct Answer - D `underset"Propyl bromide"(CH_3CH_2CH_2Br)overset"Mg/ether"to underset"Gringnard reagent"(CH_3CH_2CH_2MgBr) underset"-Mg(OH)Br"overset(H_2O, Delta)to underset"Propane"(CH_3CH_2CH_3)` |
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| 35. |
Which of the following reagents on reaction with acetylene yeild same product?A. `O_(3)//H_(2)O+H^(+)`B. `KMnO_(4)//OH^(-)//H_(2)O` (cold)C. `SeO_(2)`D. `O_(3)+H_(2)O//Zn` |
| Answer» Correct Answer - B::C::D | |
| 36. |
Which among the following will yield 2,2-dibromo butane?A. `HC-=CH+2HBrrarr`B. `CH_(3)C-=CH+2HBr rarr`C. `CH_(3)-CH=CH-CH_(3)+2HBrrarr`D. `CH_(3)-CH_(2)-C-=CH+2HBr rarr` |
| Answer» Correct Answer - D | |
| 37. |
Which of the following reactions will yeild 2,2-dibromo propane?A. `CH_(3)-CH=CH_(2)+HBr to `B. `CH_(3)C-=CH+2HBrto `C. `CH_(3)CH=CHBr+HBrto `D. `CH-=CH+2HBr` |
| Answer» Correct Answer - B | |
| 38. |
The best sequence of reactions to prepare 2-heptanone isA. propyne `overset(NaNH_(2))(to)Xoverset(n-C_(4)H_(9)Br)(to)Yoverset(H_(2)O, Hg^(2+))underset(H_(2)SO_(4))(to)`B. ethyne `overset(NaNH_(2))(to)Xoverset(n-C_(5)H_(12)Br)(to)Yoverset(H_(2)O, Hg^(2+))underset(H_(2)SO_(4))(to)`C. 1-hexyne `overset(NaNH_(2))(to)Xoverset(CH_(2)Br)(to)Yoverset(H_(2)O.Hg^(2+))underset(H_(2)SO_(4))(to)`D. 1-pentyne`overset(NaNH_(2))(to)Xoverset(C_(2)H_(5)Br)(to)Yoverset(H_(2)O, Hg^(2+))underset(H_(2)SO_(4))(to)` |
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Answer» Correct Answer - b |
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| 39. |
The most common reactions of alkenes are-A. Nucleophilic substitutionB. Electrophilic substitutionC. Electrophilic addtionD. Nucleophilic addition |
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Answer» Correct Answer - C Electrophilic reaction is characteristic reaction of alkene |
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| 40. |
The addtion of `Br_(3)` to trans-2-butene producesA. (+)2,3-dibromobutaneB. (-)2,3=dibromobutaneC. rac-2,3-dibromobutaneD. meso-2,3-dibromobutane |
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Answer» Correct Answer - D `Br_(2)` gives anti addtion. Trans alkene `to`Antiaddition `to` Erythro product. |
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| 41. |
When `2-` butyne reacts with sodamide in an inert solvent in the presence of dilute `HCl` , the product formed is `:`A. `n-`butaneB. `2-`ButeneC. `1-`ButyneD. `1-`Propyne |
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Answer» Correct Answer - c When `2-` butyne is heated with `NaNH_(2)` in an inert solvent, the sodium derivative of but`-1-`yne which is converted into but `-1-`yne by the action of dil. `HCl`. `CH_(3)-C-=C-CH_(3)+NaNH_(2)overset(Parafi n e)rarr NH_(3)+CH_(3)CH_(2)C-=CNa overset(dil. HCl)rarr underset(1-butyn e)(CH_(3)CH_(2)C-=CH` |
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| 42. |
In catalytic reduction of hydrocarbons which catalyst is mostly usedA. (a) `Pd`B. (b) `Pt//Ni`C. (c) `SiO_(2)`D. (d) Misch Metal |
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Answer» Correct Answer - b `Pt//Ni` is used in catalytic reduction of hydrocarbon |
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| 43. |
In the following reaction `C_(2)H_(2)underset(HgSO_(4)//H_(2)SO_(4))overset(H_(2)O)rarrXhArrCH_(3)CHO` What is XA. `CH_(3)CH_(2)OH`B. `CH_(3)-O-CH_(3)`C. `CH_(3)CH_(2)CHO`D. `CH_(2)=CHOH` |
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Answer» Correct Answer - D `HC-=CH underset(H_(2)O)overset(H_(2)SO_(4)//HgSO_(4))to underset("Vinyl alcohol")(CH_(2)=CHOH) Leftrightarrow underset("Acetaldehyde")(CH_(3)CHO) ` |
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| 44. |
An organic compound decolorizes `Br_2` water and also gives red ppt. with `Cu_2Cl_2` solution the compound isA. `CH_(2)=CH_(2)`B. `CH_(2)CH=CH_(2)`C. `CH_(3)-C=CH`D. `CH_(3)-C-=C-CH_(3)` |
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Answer» Correct Answer - C Since the compound decolouries `Br_(2)` water, it must be unsaturated. Since it gives red ppt. with `CuCl_(2)` it must be a terminal alkyne, i.e. `CH_(3)C-=CH` |
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| 45. |
Write structures of different isomers corresponding to the 5th member of alkyne series. Also write IUPAC names of all the isomers. What type of isomerism is exhibited by different pairs of isomers? |
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Answer» 5th member of alkyne has the molecular formula `C_(6)H_(10)`. The possible isomers are: (a) `underset("Hex-1-yne")(HC-=C-CH_(2)-CH_(2)-CH_(2)-CH_(3))` (b) `underset("Hex-2-yne")(CH_(3)-C-=C-CH_(2)-CH_(2)-CH_(3)` (c )`underset("Hex-3-yne")(CH_(3)-CH_(2)-C-=C-CH_(2)-CH_(3)` (d) `underset("3-Methylpent-1-yne")(HC-=C-underset(CH_(3))underset(|)"CH"-CH_(2)-CH_(3))` (e) `underset("4-Methylpent-1-yne")(HC-=C-CH_(2)-underset(CH_(3))underset(|)(CH)-CH_(3))` (f) `underset("4-Methlpent-2-yne")(CH_(3)-C-=C-underset(CH_(3))underset(|)(CH)-CH_(3))` (g) `underset("3,3-Dimethylbut-1-yne")(HC=C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C-CH_(3))` |
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| 46. |
Which of the following alkenes will react fastest with `H_(2)` under catalytic hydrogenation conditionsA. B. C. D. |
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Answer» Correct Answer - A During catalytic hydrogenation, the hydrogens are transferred from the catalyst to the less substitution double bond. Thus, option (a) with two R groups on the same side of the molecule is correct. |
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| 47. |
Which is the correct increasing order of the stability of isomers of pentene ? `CH_(3)-CH_(2)-CH_(20=CH_(2)` A. `1lt2lt3lt4`B. `1lt3lt2lt4`C. `4lt3lt2lt1`D. `4lt2lt3lt1` |
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Answer» Correct Answer - a Stability depends on hyperconjugation which further depends on total number of `alphaH`. |
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| 48. |
In halogenation of aromatic hydrocarbon, a halogen carrier is used which is generally a Lewis acid. The main function of this reagent is to generate the speciesA. XB. `X^(-)`C. `X^(+)`D. `X^(**)` |
| Answer» Correct Answer - C | |
| 49. |
Write the general formula for alkanes, alkenes and alkynes. |
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Answer» The general formula for alkanes is CnH2n+2, where n stands for number of carbon atoms and 2n+2 for number of hydrogen atoms in the molecule. General formula for alkenes is CnH2n General formula of alkynes is CnH2n–2. |
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| 50. |
Propanal-1 and pentan-3-one are the ozonolysis products of an alkene. What is th structural formula of alkene?A. `CH_(3)CH_(2)-underset(CH_(2)CH_(3))underset(|)(C)=CH-CH_(2)CH_(3)`B. `CH_(3)CH_(2)-CH=CH-overset(CH_(2)CH_(3))overset(|)(C)H-CH_(3)`C. `CH_(3)-underset(CH_(2)CH_(3))underset(|)(C)=overset(CH_(2)CH_(3))overset(|)(C)-CH_(3)`D. `CH_(3)CH_(2)CH_(2)CH_(2)-CH=CH-CH_(2)CH_(3)` |
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Answer» Correct Answer - A `CH_(3)CH_(2)-underset(CH_(3)-CH_(2))underset(|)(C)=O+O=underset(H)underset(|)(C)-CH_(2)-CH_(3) to CH_(3)-CH_(2)-underset(CH_(2)-CH_(3))underset(|)(C)=CH-CH_(2)-CH_(3)` |
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