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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.
| 351. |
For a molecule to be optically active, it shouldA. contain at least two `sp^(2)` hybridized carbon atomsB. not be super imposable on its mirror imageC. have tetrahedral geometry.D. super-imposable on its mirror image. |
| Answer» Correct Answer - B | |
| 352. |
Assertion: Electophilic substitution reactions in haloarenes occur slowly and require more drastic conditions as compared to those in benzene. Reason: Halogens are ortho and para-directors.A. If both assertion and reason are true and reason Is the correct explanation of assertion.B. If both assertion and reason are true but reason is not the correct explanation of assertion.C. If assetion is true but reason is false.D. If both assertion and reason are false. |
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Answer» Correct Answer - B Halogen atom because of its -I effect has some tendency to withdraw electrons from the benzene ring, as a result, the ring gets somewhat deactivated as compared to benzene. |
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| 353. |
Dissymmetric molecule are those which, areA. non super imposable mirror imageB. super imposable mirror imageC. plane of symmetryD. plane of symmetry |
| Answer» Correct Answer - A | |
| 354. |
Which branched chain isomer of the hydrocarbon with molecular mass 72 gives only one isomer of monosubstituted alkyl halide?A. IsopentaneB. NeopentaneC. IsohexaneD. Neohexane. |
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Answer» Correct Answer - B Neopentane gives only one-substituted alkyl halide. `underset("Neopentane")(CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH_(3)underset("Monohalogenation")overset(Cl_(2)//hv)tounderset("Neopentyl chloride")(CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH_(2)Cl`. |
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| 355. |
Isomer which are non super imposable mirror image are known as,A. antimeterB. metamerC. racemateD. all |
| Answer» Correct Answer - A | |
| 356. |
Consider the following reactions `1^(@)R-X+Nu^(-) to R-Nu+x^(-)` The rateof reaction maximum in the case ofA. Solvent `=H_(2)O,X=I`B. Solvent `=C Cl_(4),X=Cl`C. Solvent `=H_(2)O,X=Cl`D. Solvent `=C Cl_(4),X=I` |
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Answer» Correct Answer - D Rate of reactions is maximum when solvent is nonpolar like `CHCl_(3)C Cl_(4)` etc. and nucleophile is best leaving. `I^(-)` is best leaving nucleophile. |
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| 357. |
Methyl carboium ion si isoelectronic with,A. `CH_(4)`B. `:C Cl_(2)`C. `CH_(3)^(-)`D. `F^(-)` |
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Answer» Correct Answer - B `CH_(3)^(+)`is a methyl carboniumion having six electrons in outer most orbit. It is isoelectronic with `C Cl_(2)` (dicholor carbene), it also contains six electrons in outer most orbit. |
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| 358. |
Which of the following is lactic acid ?A. `H-underset(CH_(3)) underset(|)overset (COOH) overset(|)C-OH`B. `H-underset(CH_(3)) underset(|)overset (CH_(3)) overset(|)C-COOH`C. `H-underset(CH_(3)) underset(|)overset (CHOOH) overset(|)C-COOH`D. `H-underset(CH_(3)) underset(|)overset (H) overset(|)C-COOH` |
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Answer» Correct Answer - A While writing the Fischer projection formula on paper carbon atoms arranged in vertical line with most oxidised state carbon at top |
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| 359. |
If OH-group in lactic acidis replaced by hydrogen atom, which will happened ?A. optical activity is retainedB. optical activity is lostC. form recemic mixutreD. produce non-superimposable mirror image |
| Answer» Correct Answer - B | |
| 360. |
Which of the following statements are correct about the mechanism of this reaction ?A. A carbocation will be formed as an intermediate in the reactionB. `OH^(-)` will attach the substrate (ii) from one side and `Cl^(-)` will leave it simultaneously from other sideC. An unstable intermediate will be formed in which `OH^(-)` and `Cl^(-)` will be attached by weak bondsD. Reactions proceeds through `S_(N)1` mechanism |
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Answer» Correct Answer - A::D The reactant involved in above reaction is secondary alkyl halide. This `2^(@)` alkyl halide contain bulky group thats why it follow `S_(N)1` mechanism instead of `S_(N^(2))` mechanism, a stable carbocation will be formed as an intermediate. It is further attacked by `HO^(-)` nucleophile |
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| 361. |
Which of the following statements are correct about the kinetics of this reaction ?A. The rate of reaction depends on the concentration of only (ii)B. The rate of reaction depends on concentration of both (i) and (ii)C. Moleculirity of reaction is oneD. Molecularity of reaction is two |
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Answer» Correct Answer - A::C The above reaction follows `S_(N)1` mechanism. In `S_(N)1` mechanism formation of carbocation is a slow step. So, the rate of reaction depends upon the concentration of (ii). So, the rate of reaction depends upon the concentration of only (ii) therefore, molecularity of reaction is one. |
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| 362. |
Lactic acid showsA. metamerismB. optical isomerismC. functional isomerism with aldehydeD. tautomerism |
| Answer» Correct Answer - B | |
| 363. |
A compound contain two dissimilar chiral carbon atoms. The number of optical isomes is/areA. 2B. 3C. 4D. 1 |
| Answer» Correct Answer - C | |
| 364. |
Which of the carbon atoms present in the molecule given below are asymmetric ? A. 1,2,3,4B. 2,3C. 1,4D. 1,2,3 |
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Answer» Correct Answer - B Both `C_(2)` and `C_(3)` are asymmetric or chiral in nature. |
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| 365. |
The high reactivity of alkyl halides can be explained in tems of nature of C-X bond which is highly polarised covalent bond due to large difference in the electronegativities of carbon and halogen atom. This polarity is responsible for the nucleophilic substitution reaction of alkyl halides which mostly occur by `S_(N^(1))` and `S_(N^(2))` mechanisms. `S_(N^(1))` reaction is a two step process and in the first step R-X ionises to give carbocation (slow process). In the second step the nucleophilic attacks the carbocation from either side to form the prodcut (fast process) . In `S_(N^(1))` reaction there can be reacemization and inversion . `S_(N^(1))` reaction is favoured by heavy (bulky) groups on the carbon atom attached to halogens. i.e., `R_(3)C-Xgt R_(2)CH-Xgt R_CH_(2)X gt CH_(3)X. " In " S_(N^(2))` reaction the strong nucleophilie `OH^(-)` attacks from the opposite side of the chlorine atom to give an inyermediate (transition state). which breaks to yield the product (alcohol) and leaving `(X^(-))` group. The alcohol has a configuration opposite to that of the bromide and is said to proceed with inversion of configuration. `S_(N^(2))` reaction is favoured by small groups on the carbon atom attached to halogen i.e., `CH_(3)-X gt R-CH_(2)X gt R_(2) CHX gt R_(3) C-X` `S_(N^(1))` reaction of optically active alkyl halide leads to :A. retention of configurationB. racemisationC. inversion of configurationD. none of these |
| Answer» Correct Answer - B | |
| 366. |
The high reactivity of alkyl halides can be explained in tems of nature of C-X bond which is highly polarised covalent bond due to large difference in the electronegativities of carbon and halogen atom. This polarity is responsible for the nucleophilic substitution reaction of alkyl halides which mostly occur by `S_(N^(1))` and `S_(N^(2))` mechanisms. `S_(N^(1))` reaction is a two step process and in the first step R-X ionises to give carbocation (slow process). In the second step the nucleophilic attacks the carbocation from either side to form the prodcut (fast process) . In `S_(N^(1))` reaction there can be reacemization and inversion . `S_(N^(1))` reaction is favoured by heavy (bulky) groups on the carbon atom attached to halogens. i.e., `R_(3)C-Xgt R_(2)CH-Xgt R_CH_(2)X gt CH_(3)X. " In " S_(N^(2))` reaction the strong nucleophilie `OH^(-)` attacks from the opposite side of the chlorine atom to give an inyermediate (transition state). which breaks to yield the product (alcohol) and leaving `(X^(-))` group. The alcohol has a configuration opposite to that of the bromide and is said to proceed with inversion of configuration. `S_(N^(2))` reaction is favoured by small groups on the carbon atom attached to halogen i.e., `CH_(3)-X gt R-CH_(2)X gt R_(2) CHX gt R_(3) C-X` Which among the following will not give `S_(N^(1))` reaction?A. `CH_(3)-underset(C_(6)H_(5))underset(|)(CH)-Br`B. `(CH_(3))_(3)C-Br`C. `CH_(3)CH_(2)I`D. `(C_(6)H_(5))_(2)-underset(CH_(3))underset(|)C-Cl` |
| Answer» Correct Answer - C | |
| 367. |
The high reactivity of alkyl halides can be explained in tems of nature of C-X bond which is highly polarised covalent bond due to large difference in the electronegativities of carbon and halogen atom. This polarity is responsible for the nucleophilic substitution reaction of alkyl halides which mostly occur by `S_(N^(1))` and `S_(N^(2))` mechanisms. `S_(N^(1))` reaction is a two step process and in the first step R-X ionises to give carbocation (slow process). In the second step the nucleophilic attacks the carbocation from either side to form the prodcut (fast process) . In `S_(N^(1))` reaction there can be reacemization and inversion . `S_(N^(1))` reaction is favoured by heavy (bulky) groups on the carbon atom attached to halogens. i.e., `R_(3)C-Xgt R_(2)CH-Xgt R_CH_(2)X gt CH_(3)X. " In " S_(N^(2))` reaction the strong nucleophilie `OH^(-)` attacks from the opposite side of the chlorine atom to give an inyermediate (transition state). which breaks to yield the product (alcohol) and leaving `(X^(-))` group. The alcohol has a configuration opposite to that of the bromide and is said to proceed with inversion of configuration. `S_(N^(2))` reaction is favoured by small groups on the carbon atom attached to halogen i.e., `CH_(3)-X gt R-CH_(2)X gt R_(2) CHX gt R_(3) C-X` An `S_(N^(2))` reaction at an asymmetric carbon of a compound always gives:A. an enantiomer of the substrateB. a product with opposite optical rotationC. a mixture of diastereomersD. a single stereoisomer |
| Answer» Correct Answer - D | |
| 368. |
The high reactivity of alkyl halides can be explained in tems of nature of C-X bond which is highly polarised covalent bond due to large difference in the electronegativities of carbon and halogen atom. This polarity is responsible for the nucleophilic substitution reaction of alkyl halides which mostly occur by `S_(N^(1))` and `S_(N^(2))` mechanisms. `S_(N^(1))` reaction is a two step process and in the first step R-X ionises to give carbocation (slow process). In the second step the nucleophilic attacks the carbocation from either side to form the prodcut (fast process) . In `S_(N^(1))` reaction there can be reacemization and inversion . `S_(N^(1))` reaction is favoured by heavy (bulky) groups on the carbon atom attached to halogens. i.e., `R_(3)C-Xgt R_(2)CH-Xgt R_CH_(2)X gt CH_(3)X. " In " S_(N^(2))` reaction the strong nucleophilie `OH^(-)` attacks from the opposite side of the chlorine atom to give an inyermediate (transition state). which breaks to yield the product (alcohol) and leaving `(X^(-))` group. The alcohol has a configuration opposite to that of the bromide and is said to proceed with inversion of configuration. `S_(N^(2))` reaction is favoured by small groups on the carbon atom attached to halogen i.e., `CH_(3)-X gt R-CH_(2)X gt R_(2) CHX gt R_(3) C-X` The main product formed in the following reaction is `CH_(3)-underset(CH_(3))underset(|)(CH)-CH_(2)Br+CH_(3)CH_(2)O^(-)overset(S_(N^(1)))(to)`A. `CH_(3)-underset(CH_(3))underset(|)(CH)-CH_(2)OCH_(2)CH_(3)`B. `CH_(3)-overset(CH_(3))overset(|)underset(CH_(3))underset(|)C-OCH_(2)CH_(3)`C. `CH_(3)-underset(CH_(3))underset(|)(CH)-CH_(2)OH`D. `CH_(3)-overset(CH_(3))overset(|)underset(CH_(3))underset(|)C-OH` |
| Answer» Correct Answer - B | |
| 369. |
The high reactivity of alkyl halides can be explained in terms of nature of `C-X` bond which is a highly polarised covalent bond. This polarity is responsible for the nucleophilic substitution reaction of alkyl halides which jmostly occur by `S_(N^(1)) and S_(N^(2))` mechanisms. `S_(N^(1))` reaction is a two step process and in the first step `R-X` ionises to give carbocation (slow process). IN the second step, the nucleophile attacks the carbocation from either side to form the product (fast process). IN `S_(N^(1))` reaction, there can be racemization and inversion. `S_(N^(1))` reaction is favoured by heavy (bulky) group on the carbon atom attached to halogens. IN `S_(N^(2))` reaction, the strong nucleophile `OH^(-)` attacks fromt he opposite side Of the halogen atom to give an intermediate (transition state), which breaks to yields to product (alcohol) and leaving group `(X^(-))`. The alcohol has a configuratio opposite to that of the halide and is said to proceed with inversion of configuration. `S_(N^(2))` reaction is favoured by small groups on the carbon atom attached to halogen. Q. Which among the following will not give `S_(N^(1))` reaction?A. `CH_(3)-underset(C_(6)H_(5))underset(|)(C)H-Br`B. `(CH_(3))_(3)C-Br`C. `CH_(3)CH_(2)-I`D. `(C_(6)H_(5))_(2)underset(CH_(3))underset(|)(C)-Cl`. |
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Answer» Correct Answer - C Primary alkyl halides preferable react by `S_(N^(2))` mechanism. |
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| 370. |
The actual order of reactivity ofalkyl halide isA. `R-Cl gt R-Br gt R-I`B. `R-I gt R-Br gt Cl`C. `R-Br gt R-Cl gt RI`D. `R-I gt R-Cl gt R-Br` |
| Answer» Correct Answer - B | |
| 371. |
Accroding to polarity, the expeceted reactivity of R-X isA. `R-Cl gt R-Br gt R-I`B. `R-l gt R-I gt R-Br`C. `R-I gt R-Br gt R-Cl`D. `R-Br- gt R-I gt R-Cl` |
| Answer» Correct Answer - A | |
| 372. |
Vinly chloride undergoesA. addition reactionB. elimination reactionC. substitution reactionD. none of these |
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Answer» Correct Answer - A `CH_(2)=CHCl+HCl to CH_(3)-CHCl_(2)` is a addition reaction. |
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| 373. |
In Swarts reactiion reagent used is are/A. `AgF`B. `Ag_(2)F_(2)`C. `COF_(2)`D. one of these |
| Answer» Correct Answer - D | |
| 374. |
Which of the following is Swart reaction ?A. `R-Br +Nal overset("dry acetone") to`B. `R-OH-+HCl overset("Anhy" ZnCl_(2)) to`C. `R-X+NH_(3) overset("alc.& excess") to`D. `R-Cl+HgF_(2) to` |
| Answer» Correct Answer - D | |
| 375. |
The correct order of B.P. of R-XA. `R-I gt R-Br gt R-Cl`B. `R-Cl gt R-Br gt R-I`C. `R-I gt R-Cl gt R-Br`D. `R-Cl gt R-I gt R-Br` |
| Answer» Correct Answer - A | |
| 376. |
The corret order of B.P of following compounds is A. `4 gt 3 gt 2 gt 1`B. `4 gt 2 gt 3 gt 1`C. `1 gt 2 gt 3 gt 4`D. `1 gt 3 gt 2 gt 4` |
| Answer» Correct Answer - D | |
| 377. |
When alkyl idodie are exposed to light producesA. alkane and HIB. alkanane and `I_(2)`C. alkene ana HID. alkene and `I_(2)` |
| Answer» Correct Answer - B | |
| 378. |
The n-propyl iodide is heated with aq. KOH the product obtained isA. 2-propanolB. 1-propanolC. porpeneD. cyclopropane |
| Answer» Correct Answer - B | |
| 379. |
Iodoform can be used in medicine as anA. antisepticB. anaestheticC. antifebrinD. hypnotic |
| Answer» Correct Answer - A | |
| 380. |
What happens when `(+)2- `iodobutane is treated with Nal in acetone? |
| Answer» `(+) 2-` lodobutane on treatment with Nal in acetone gives racemic `(+-) `2- lodobutane | |
| 381. |
Boiling point of alkyl halides in influenced byA. London force of attractionB. dipole-dipole attractionC. both of the aboveD. none of the above |
| Answer» Correct Answer - C | |
| 382. |
Which has maximum boiling point ?A. `CH_(2)OH`B. `CH_(3)CH_(2)I`C. `CH_(3)CH_(2)Cl`D. `CH_(3)CH_(2)Br` |
| Answer» Correct Answer - B | |
| 383. |
Which of the following is a primary halide ?A. Isopropyl iodideB. Secondary butyl iodideC. Tertiary buty bromideD. Neo hexyl chloride |
| Answer» Correct Answer - D | |
| 384. |
Which is the correct increasing order of boiling points of the following compounds? 1-Bromoethane,1-Bromopropane,1-Bromobutane,BromobenzeneA. Bromobenzenelt1-Bromobutanelt1-Bromopropanelt1-BromoethaneB. Bromobenzenelt1-Bromoethanelt1-Bromopropane,1-BromobutaneC. 1-Bromopropanelt1-Bromobutanelt1-BromoethaneltBromobenzeneD. 1-Bromoethanelt1-Bromopropanelt1-BromobutaneltBromobenzene |
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Answer» Correct Answer - D For the same halogen, boiling point increases as the size of the hydrocarbon part increases. |
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| 385. |
In which of the following compounds, the C-Cl bond ionisation shall give most stable carbonium ion ?A. `CH_(3)- overset(Cl) overset(|)CH-CH_(3)`B. C. D. `O_(2)N-CH_(2)-CH_(2)-Cl` |
| Answer» Correct Answer - C | |
| 386. |
Arrange the compound in order of increasing boiling points . 1- Chloropropane , Isopropyl chloride , 1-Chlorobutane . |
| Answer» Isoporpylchloride , 1-Chloropropane , 1- Chlorobutane . Isopropylchloride being branched has lower b.p. than 1-Chloropropane . | |
| 387. |
Alkyl halide from the pair would react more rapidly by an `S_(N) 2` mechanism ? Explain your answer . `CH_3 CH_(2) underset(Br)underset(|)(C)HCH_(3) or H_(3) C - overset(CH_(3))overset(|)underset(CH_(3))underset(|)(C)- Br` |
| Answer» `CH_(3)CH_(2)underset(Br)underset(|)(C)H CH_(3)` Secondary halide reacts faster than tertiary halide . | |
| 388. |
The removal of two atoms or groups one generally hydrogen `(H^(+))` and the other a leaving group `(L^(-))` resulting in the formation of unsaturated compound is known as elimination reaction. In `E_(1)` (elimination) reactions the C-L bond is broken heterolytically (in step 1) to form a carbocation (as in`S_(N^(1))` reaction) in which `(L^(-))` is lost (rate determining step). The carbocation (in step 2) loses a proton from the `beta-` carbon atom by a base (nucleophile) to form an alkene. `E_(1)` reaction is favoured in compounds in which the leaving group is at secondar `(2^(@))` or tertiary`(3^(@))` Position. In `E_(2)` (elimination) reactions two sigma bonds are broken and a `pi-`bond is formed simultaneously.`E_(2)` reactions occur in one step through a transition state. `E_(2)` reactions are most common in haloalkanes (particulary `1^(@)`) and better the leaving group higher is the `E_(2)` reaction. In `E_(2)` reactions, both the leaving groups should be antiplaner. `E_(1) cb` (Elimination unimolecular conjugate base) reaction involves the removal of proton by a conjugate base (step 1) to produce carbanion which loses a leaving group to form an alkene (step 2) and is a slow step 2-Bromopentane is heated with potassium ethoxide in ethanol. The major product obtained is : |
| Answer» Correct Answer - D | |
| 389. |
`S_(N^(1))` reaction is a first order nucleophilic substitution e.g. `CH_(3)-overset(CH_(3))overset(|)underset(CH_(3))underset(|)C-Br+H_(2)Oto CH_(3)-overset(CH_(3))overset(|)underset(CH_(3))underset(|)C-OH+HBr` The concentration of nucleophile does not appear in the rate law expression. Reaction rate k[RX] In a mulptistep organic reaction , the rate-limiting step is the slowest step . Rate determining step is represented by the following energy level diagram: A reaction energy level diagram for an `S_(N^(1))` reaction .The rate limiting step is spontaneous dissociation of an alkyl halide to give a carbocation intermediate: In `S_(N^(1))` reaction the hybridization changes in rate determination step. Select the correct change among the following:A. from `sp^(3)" to "sp^(2)`B. from `sp^(2) " to "sp^(3)`C. from `sp^(2) " to "sp`D. from sp to `sp^(2)` |
| Answer» Correct Answer - A | |
| 390. |
In which ot the following Kharsch-Myo effect operate?A. `CH_(3)CH=CHCH_(3)+HBr`B. `CH_(3)CH_(2)CH=CH_(2)+HBr`C. `CH_(3)CH_(2)CH=CH_(2)+HCl`D. `CH_(3)CH=CH_(2)+HI` |
| Answer» Correct Answer - B | |
| 391. |
A Grignard reagent is prepared by the action of magnesium in dry ether on:A. `C_(2)H_(5)OH`B. `C_(2)H_(6)`C. `C_(2)H_(5) Cl`D. `C_(2)H_(5)CN` |
| Answer» Correct Answer - C | |
| 392. |
Arrange the following in decreasing order of reactivity towards aqueous KOH. (i). `CH_(2)=CH-Cl` (ii). `C_(6)H_(5)CH_(2)Cl` (iii). `CH_(2)=CH-CH_(2)Cl` (iv). `C_(2)H_(5)-Cl` |
| Answer» (ii)gt(iii)gt(iv)gt(i) | |
| 393. |
Chloroform is stored in dark coloured bottles. Explain in not more than two sentences.A. it reacts with clear glassB. it undergoes chlorination in tranparent glass bottlesC. it is oxidised to poisonous gas, phosgene in sunlightD. it starts burning when exposed to sunlight. |
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Answer» Correct Answer - C Chloroform gets oxidised by air in sunlight to poisonous phosgene gas. `2CHCl_3+O_2overset(hv)to underset("Phosgene")(2COCl_2)+2HCl` |
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| 394. |
Alkyl halides react with metallic sodium in dry ether producingA. alkanes with same number of carbon atomsB. alkanes with double the number of carbon atomsC. alkenes with triple the number of carbon atomsD. alkenes with same number of carbon atoms. |
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Answer» Correct Answer - B `R-underset("Alkyl halide")(X+2Na+X)-Roverset("dry ether")tounderset("Alkane")(R-R)+underset("halide")underset("Sodium")(2Na-X)` |
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| 395. |
Product P (major ) isA. B. C. D. |
| Answer» Correct Answer - 4 | |
| 396. |
Statement -1 : Tertiary alkyl halides are more reactive than `1^(@)` alkyl towards elimination Statement -2 : Tertiary alkyl halides give more stable caranion |
| Answer» Correct Answer - C | |
| 397. |
Which is most stable radial ?A. `CH_(3)`B. `CH_(2) =CH -CH_(2)`C. `CH_(3) -CH_(2)`D. |
| Answer» Correct Answer - 2 | |
| 398. |
The reagent R isA. `NH_(3)`B. `H_(2)O`C. `KCN`D. Na `//` either |
| Answer» Correct Answer - 4 | |
| 399. |
Which one of the following compounds undergoes predominantly `S_(N^(2))` reaction with aqueous NaOH in polar aerotic solvent? |
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Answer» Correct Answer - B `-NO_(2)` group is an electron withdrawing group with strong. -R or -M effect. This enables the cleavages of `C-Cl` bond in polar aprotic solvent easily. As a result, the compound (d) mainly responds to `S_(N^(2))` reaction. |
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| 400. |
Acetone is mixed with bleaching powder to giveA. chloroformB. acetaldehydeC. ethanolD. phosgene |
| Answer» Correct Answer - A | |