InterviewSolution
Saved Bookmarks
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.
| 601. |
Haloalkanes contain halogen atom(s) attached to the `sp^(3)`hybridised carbon atom of an alkyl group. Identify haloalkene from the following compounds.A. 2-Bromopentane.B. Vinyl chloride (chloroethene)C. 2-chloroacetophenoneD. Trichloromethane |
|
Answer» Correct Answer - A::D (a,d) are both haloalkanes. |
|
| 602. |
Haloalkanes contain halogen atom(s) attached to the `sp^(3)`hybridised carbon atom of an alkyl group. Identify haloalkene from the following compounds.A. 2-bromopentaneB. Vinyl chloride (chloroethane)C. 2-chloroacetophenonD. Trichloromethane |
|
Answer» Correct Answer - A::D In the structure of 2-bromopentane `(CH_(3)-underset(Br)underset(|)"CH"-CH_(2)-CH_(2)-CH_(3))` and trichloromethane `(Cl-underset(Cl)underset(|)overset(Cl)overset(|)C-H)`, halogen to the `sp^(3)` hybridised carbon atom of an alkyl group. |
|
| 603. |
Haloalkanes contain halogen atom(s) attached to the `sp^(3)`hybridised carbon atom of an alkyl group. Identify haloalkene from the following compounds.A. Only (ii)B. (ii) and (iv) onlyC. (i) and (iv) onlyD. (i),(ii) and (iii) only |
| Answer» Correct Answer - C | |
| 604. |
Name the following halides according to IUPAC system and classify them asalkyl, allyl, benzyl (primary, secondary, tertiary), vinyl or aryl halides: (i) `(CH_(3))_(2)CHCH(Cl)CH_(3) , (ii) CH_(3)CH_(2)CH(CH_(3))CH(C_(2)H_(5))Cl` (iii) `CH_(3)CH_(2)C(CH_(3))_(2)CH_(2)I , (iv) (CH_(3))_(3)C CH_(2)CH(Br)C_(6)H_(5)` (v) `CH_(3)CH(CH_(3))CH(Br)CH_(3) , (vi) CH_(3)C(C_(2)H_(5))_(2)CH_(2)Br` `(vii) CH_(3)C(Cl)(C_(2)H_(5))CH_(2)CH_(3) , (viii) CH_(3)CH=C(Cl)CH_(2)CH(CH_(3))_(2)` (ix) `CH_(3)CH=CHC(Br)(CH_(3))_(2) (x) p-ClC_(6)H_(4)CH_(2)CH(CH_(3))_(2)`(xi) `m-ClCH_(2)C_(6)H_(4)CH_(2)C(CH_(3))_(3) , "(xii)" o-Br-C_(6)H_(4)CH(CH_(3))CH_(2)CH_(3)` |
|
Answer» (i)2-Chloro-3methylbutane, `2^(@)` alkyl halide (ii) 3-Chloro-4methyl hexane, `2^(@)`alkyl halide (iii) 1-lodo-2,2-dimethylbutane, `1^(@)` alkyl halide (iv) l-Bromo-3, 3-dimethyl-1-phenylbutane, `2^(@)` benzylic halide (v) 2-Bromo-3-methylbutane, `2^(@)`alkyl halide (vi) 1-Bromo-2-ethly-2-methylbutane, `1^(@)` alkyl halide (vii) 3-Chloro-3-methypentane, `3^(@)` alkyl halide (viii) 3-Chloro-5-methylhex-2-ene, vinylic halide (ix) 4-Bromo-4-methylpent-2-ene, allylic halide (x) 1-Chloro-4-(2-methylpropyl) benzene, aryl halide (xi) 1-Chloromethyl-3-(2,2-dimethylpropyl) benzene, `1^(@)` benzylic halide. (xii) 1-Bromo-2-(l-methylpropyl) benzene,aryl halide. |
|
| 605. |
When pure chloroform is shaken with silver nitrate solution we get :A. a yellow ppt. of AgIB. a white ppt. of AgCIC. silver mirrorD. no precipitate |
| Answer» Correct Answer - A | |
| 606. |
When pure chloroform is shaken with silver nitrate solution we get :A. No precipitateB. a yellow ppt. of AgIC. a white ppt. of AgCID. acetylene is liberated |
| Answer» Correct Answer - A | |
| 607. |
The major organic compound formed by the reaction of 1,1,1-trichloroethane with silver powder is:A. acetyleneB. etheneC. but-2-yneD. but-2-ene |
|
Answer» Correct Answer - C But-2-yne is formed `CH_(3)C Cl_(3)+2Ag+CH_(3)C Cl_(3)+CH_(3)C Cl_(3)tounderset("but-2-yne")(CH_(3)C -= C CH_(3)+6AgCl)` Only (a) Hs specific dipole moment. All other are symmetrical and have `mu=0`. |
|
| 608. |
Which reagent will you use for the following reaction ? `CH_(3)CH_(2)CH_(2)CH_(3)toCH_(3)CH_(2)CH_(2)CH_(2)Cl+CH_(3)CH_(2)CHClCH_(3)`A. `Cl_2//UV` lightB. `NaCl+H_2SO_4`C. `Cl_2` gas in darkD. `Cl_2` gas in the presence of iron in dark |
|
Answer» Correct Answer - A Direct chlorination of alkanes takes place in presence of sunlight (UV light). |
|
| 609. |
Write the mechanism of the following reactions (i). `CH_(2)Cl+OH^(-)toCH_(3)OH+Cl^(-)` (ii). `CH_(3)-CH_(2)-overset(Cl)overset(|)(C)H-CH_(3)+OH^(-)toCH_(3)-CH=CH-CH_(3)+Cl^(-)`. |
|
Answer» (i) The reaction follows `S_(N^(2))` mechanism. (ii). The reaction follows `E_(2)` mechanism. |
|
| 610. |
How do you convert: (i). Chlorobenzene to biphenyl (ii). Propene to 1-iodopropane (iii). 2-bromobutane to but-2-ene. |
|
Answer» (i). It involved fittig reaction (ii). `CH_(3)-CH=CH_(2)underset(("Peroxide"))overset("HBr")tounderset("1-Bromopropane")(CH_(3)-CH_(2)-CH_(2)-Br)overset(NaI//"acetone")tounderset("1-Iodopropane")(CH_(3)-CH_(2)-CH_(2)-I)` (iii). `underset("2-Bromobutane")(CH_(3)-underset(Br)underset(|)(C)H-CH_(2)-CH_(3))overset(KHO(alc.))tounderset("But-2-ene")(CH_(3)-CH=CH-CH_(3))`. |
|
| 611. |
Karl Ziegler reported that alkenes react with N-bromosuccinimide (NBS) in presence of light to give products resulting from substitution of hydrogen by bromine at the allylic position i.e., the position next to the double bond. Let us consider the halogenation of cyclohexane. Energy level diagram for allylic vinylic and alkylic free redicals is given below: Select the correct statement(s) among the following :A. allylic free radical is stabilised by delocalisationB. Vinylic free radical is stablilised by hyperconjugationC. Alkyl free radicals are stabilised by hyperconjugationD. Alkylic free radical is stabilised by hyperconjugation |
| Answer» Correct Answer - A::C | |
| 612. |
Karl Ziegler reported that alkenes react with N-bromosuccinimide (NBS) in presence of light to give products resulting from substitution of hydrogen by bromine at the allylic position i.e., the position next to the double bond. Let us consider the halogenation of cyclohexane. Energy level diagram for allylic vinylic and alkylic free redicals is given below: Which of the following sequences is correct about C-H bond energy ?A. (C-H)Vinylic`gt`(C-H) Alkylic `gt` (C-H) AllylicB. (C-H) Vinuylic `lt`(C-H) Alkylic `lt` (C-H) AllkylicC. (C-H) Alkylic ` lt `(C-H)Vinylic `lt`(C-H) AllylicD. (C-H) Vinylic =(C-H) Alkylic =(C-H)Allylic |
| Answer» Correct Answer - A | |
| 613. |
Karl Ziegler reported that alkenes react with N-bromosuccinimide (NBS) in presence of light to give products resulting from substitution of hydrogen by bromine at the allylic position i.e., the position next to the double bond. Let us consider the halogenation of cyclohexane. Energy level diagram for allylic vinylic and alkylic free redicals is given below: Consider the three types of C-H bonds in cyclohexene. Which of the following `is // are `correctly matched?A. A-Vinylic C-H bondB. B-Allylic C-H bondC. C-Alkylic C-H bondD. All of these |
| Answer» Correct Answer - D | |
| 614. |
Karl Ziegler reported that alkenes react with N-bromosuccinimide (NBS) in presence of light to give products resulting from substitution of hydrogen by bromine at the allylic position i.e., the position next to the double bond. Let us consider the halogenation of cyclohexane. Energy level diagram for allylic vinylic and alkylic free redicals is given below: Select the correct statement(s) among the following :A. B. C. D. Connot be predicted |
| Answer» Correct Answer - C | |
| 615. |
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 Isopropyl chloride on heating with concentrated solution of ethanolic KOH gives mainly:A. propan-1-oIB. propan-2-oIC. propeneD. isopropyl ethyl ether |
| Answer» Correct Answer - C | |
| 616. |
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-Bromonbutane on heating with concentrated solution of alcoholic KOH gives major product as :A. but -1-eneB. but-2-eneC. butan-2-oID. 2-methylpropene |
| Answer» Correct Answer - B | |
| 617. |
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 Neopentyl bromide undergoes dehydrohalogenation to give alkene even though it has no `beta-`hydrogen.This is due to :A. `E_(2)`mechanismB. `E_(1)` mechanismC. due to rearrangement of carbocation by `E_(1)` mechanismD. `E_(1)` cb mechanism |
| Answer» Correct Answer - C | |
| 618. |
In the following compounds nucleophile and the leaving groups are in the same molecule : these dual nature species can undergo intramolecular and intermolecular nucleophilic substitution Intramolecular substitution reaction is possible in :A. `I,II`B. `II,III`C. `III,IV`D. `IV` |
|
Answer» Correct Answer - C In I and II, intramolecular reaction will not be possible because they will give strained ring. |
|
| 619. |
Which is the correct increasing order of boiling points of the following compounds ? 1-bromoethane, 1-bromobutane, 1-bromopropane, 1-bromobenzeneA. Bromobenzene `lt` 1-Bromobutane `lt` 1-Bromopropane `lt` 1-BromoethaneB. Bromopropane `lt` 1-bromoethane `lt` 1-bromopropane `lt `1-romobutane.C. 1-Bromopropane `lt` 1-Bromobutane `lt` 1-bromoethane `lt` BromobenzeneD. 1-Bromoethane`lt` 1-bromopropane `lt1-` bromobutane `lt` bromobenzene. |
|
Answer» Correct Answer - D It is the correct increasing order of boiling points. For the same halogen atom, boiling point increases with the increase in the size of alkyl group. |
|
| 620. |
Which is the correct increasing order of boiling pointsA. Butane`lt`1-chlorobutane`lt`1-bromobutane`lt`1-iodobutaneB. 1-iodobutane`lt`1-bromobutane`lt`1-chlorobutane`lt`ButaneC. Butane`lt`1-iodobutane`lt`1-bromobutane`lt`1-chlorobutaneD. Butane`lt`1-chlorobutane`lt`1-iodobutane`lt`1-bromobutane |
|
Answer» Correct Answer - A Higher the surface area, higher will be the intermolecular forces of attraction and thus boiling point too. Boiling point increases with increase in molecular mass of halogen atom for the similar type of alkyl halide. Butane has no halogen atom and rest of all three compounds are halo derivatives of butane. Atomic mass of iodine is highest so the boiling point of 1-iodobutane is maximum among all the given compounds and hence, option (a) incorrect |
|
| 621. |
Which of the following statements are correct about the above reaction ?A. (i) and (v) both are nucleophilesB. In (iii) carbon atom is `sp^(3)` hybridisedC. In (iii) carbon atom is `sp^(2)` hybridisedD. (i) and (v) both are electrophiles |
|
Answer» Correct Answer - C In the above reaction, `""^(-)OH` and `""^(-)CI` both are electron rich species as they are holding the negative charge. So, they are nucleophiles The above reaction show `S_(N)2` mechanism, carbon of alkyl halide is `sp^(3)` hybridised. During this mechanism, the breaking of C-X bond and formation of new bond (C-Nu) occur simultaneously through a transition state in which carbon atom is approximately `sp^(2)` hybridised. |
|
| 622. |
Ullmann reaction is given by :A. `C_(6)H_(5)-CI`B. C. D. |
| Answer» Correct Answer - D | |
| 623. |
Which is the correct increasing order of boiling points of the following compounds ? 1-bromomethane, 1-bromobutane, 1-chlorobutane, ButaneA. Bromobenzene`lt`1-bromobutane`lt`1-bromopropane`lt`1-bromoethaneB. Bromobenzene`lt`1-bromoethane`lt`1-bromopropane`lt`1-bromobutaneC. 1-bromopropane`lt`1-bromobutane`lt`1-bromoethane`lt`BromobenzeneD. 1-bromoethane`lt`1-bromopropane`lt`1-bromobutane`lt`Bromobenzene |
|
Answer» Correct Answer - D Boiling point increases with increase in size of hydrocarbon part for the same haloalkanes All the given haloalkenes contain same halogen atom i.e., bromine but the number of carbon atoms in hydrocarbon part of the molecule are increasing from ethane to benzene. So, the boiling point is minimum for 1-bromoethane and maximum for 1-bromobenzene. |
|
| 624. |
What is the common name of `(CH_(3))_(2)CHCH_(2)Br`? |
| Answer» Correct Answer - Isobutylbromide | |
| 625. |
Select correct statement (s) about following reaction : `C_(2) H_(5) O^(-) + CH_(3) CH_(2) overset(Br) overset(|) CHCH_(3) overset(C_(2)H_(5)OH) to`A. It is termed as `beta`- elimination reactionB. `C_(2)H_(5)O^(-)` is a Bronsted -baseC. Produced are 1-butene and 2-buteneD. All are correct statements |
|
Answer» Correct Answer - D `CH_(3) CH_(2) CH_(3) overset(AlBr_(3)) toCH_(3)CHClCH_(3)` `2CH_(3)CHClCH_(3) +2Na overset("dry ether") to (CH_(3))_(2)CH-CH(CH_(3))_(2)` |
|
| 626. |
Which of the following is ambidantate nucleophile?A. OHB. `NH_(2)`C. ROD. CN |
| Answer» Correct Answer - D | |
| 627. |
The reaction of `C_(6) H_(5) CH=CHCH_(3)` with HBr produces :A. `C_(6)H_(5)- underset(Br) underset(|)(CH)CH_(2)-CH_(3)`B. `C_(6)H_(5)-CH_(2) - underset (B) underset(|) (CH)CH_(3)`C. `C_(6)H_(5)-CH_(2)-CH_(2)-CH_(2)-Br`D. |
| Answer» Correct Answer - A | |
| 628. |
Some statement are given below about `SN^(1)` reaction 1. `DeltaH` is negative 2. the first step is slower than second step 3. kinetics depends on alkyl halide taken 4. product formed as racemisation of configuration Among the above the incorrect statement(s) is/areA. only 4B. only 3 and 4C. only 1 and 2D. none of these |
| Answer» Correct Answer - D | |
| 629. |
The halogen atom from haloalkane can be replaced by nucleophile such asA. `NH_(2)^(-)`B. `CN^(-)`C. `RO^(-)`D. all of these |
| Answer» Correct Answer - D | |
| 630. |
Which of the following is /are organometallic compound(s) ? 1) `C_(2)H_(5)MgI` 2) `C_(2)H_(5)ONa` 3) `(CH_(3)COO)_(2)Ca` 4) `CH_(3)COOK`A. only 1B. only 1 and 2C. only 1, 3D. all of these |
| Answer» Correct Answer - A | |
| 631. |
Assertion: Addition of `Br_(2)` to but-1-ene gives two optical isomers. Reason: The product contains one asymmetric carbon.A. If both assertion and reason are correct and reason is correct explanation for assertionB. If both assertion and reason are correct but reason is not correct explanation for assertion.C. If assertion is correct but reason is incorrect.D. if both assertion and reason are incorrect. |
|
Answer» Correct Answer - A Reson in the correct explanation for assertion. |
|
| 632. |
If 3-chloromethylhexane is treated with `C_(2)H_(5)Ona//C_(2)H_(5)OH, E_(2)` elimination reaction takes place predominantly. How many different alkenes would be formed ? |
| Answer» Correct Answer - 5 | |
| 633. |
How many stereoisomers are possible for chlorination of `C_(5)H_(12) ?`A. 3B. 4C. 5D. 6 |
| Answer» Correct Answer - D | |
| 634. |
The number of chlorine atoms in `C_(2)Cl_(X)` is |
| Answer» `C_(2)Cl_(6)` (six). | |
| 635. |
How many types of substituted alcohols (stereoisomers are not considered) are possible in the given reaction ? |
| Answer» Correct Answer - 3 | |
| 636. |
Find out numbers of possible `E_(1)` products from following reaction . |
| Answer» Correct Answer - 4 | |
| 637. |
How many stereoisomers are possible for 2-bromo-3-chlorobutane? |
| Answer» `CH_(3)-underset(Br)underset(|)overset(**)(C)H-underset(Cl)underset(|)overset(**)(C)H-CH_(3)` No. of chiral centres=2, No. of stereoisomers`=2^(n)=4`. | |
| 638. |
How many substrates will show rearrangement during `S_(N^(1))` reaction? |
| Answer» Correct Answer - 6 | |
| 639. |
Assertion: Thionyl chloride reacts with straight chain primary alcohols without any rearrangement. Reason: `SO_(2)` escapes from the reaction mixture.A. If both assertion and reason are correct and reason is correct explanation for assertionB. If both assertion and reason are correct but reason is not correct explanation for assertion.C. If assertion is correct but reason is incorrect.D. if both assertion and reason are incorrect. |
|
Answer» Correct Answer - B Correct explanation: No carbocation intermediate is formed in the substitution reaction. |
|
| 640. |
Which of the following phreases are not correvlty associated with `S_(N^(1))` reaction ?(I) Rearrangement is possible (II) Rate si affected by polarity of solvent (III) the strength of the nuclephile is important in determining rate(IV) the reacityity series is tertiary gt secondary gt promany (V) proceeds with complete inversion of configguationA. 5 onlyB. 3 onlyC. 2,3,5D. 3,5 only |
|
Answer» Correct Answer - C The statements 3&5 are not associated with `S_(N^(1))` reaction. The correct statements are strength of the nucleophile is involved in the slow or rate determining step. In `S_(N^(1))` reaction, inversion may be either partial or complete. |
|
| 641. |
Assertion. `t`-Butyl Methyl ether is not prepared by the reaction of `t-`butyl bromide with sodium methoxide. Reason: Sodium methoxide is a strong nucleophile.A. If both (A) and (R) are correct and (R) is the correct explanation of (A)B. If both (A) and (R) are correct but (R) is not the correct explanation of (A)C. If (A) is correct but (R) is incorrect.D. If (A) is incorrect but (R) is correct. |
| Answer» Correct Answer - B | |
| 642. |
(A) Styrene on reaction with HBr gives 2-bromo-2-phenyl ethane. (R) Benzyl radical is more stable than alkyl radical .A. If both (A) and (R) are correct and (R) is the correct explanation of (A)B. If both (A) and (R) are correct but (R) is not the correct explanation of (A)C. If (A) is correct but (R) is incorrect.D. If both (A) and (R) are incorrect. |
| Answer» Correct Answer - E | |
| 643. |
`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 the graph 3 for `S_(N^(1))` reaction the rate limiting step is the spontaneous dissociation of alkyl halide and is given byA. ABB. ACC. ADD. DE |
| Answer» Correct Answer - A | |
| 644. |
`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: Select the correct statement(s) about the graph 2:A. first step is rate determining and it is endothermicB. first step is rate determining and it is exothermicC. second step is rate determining and it is exothermicD. second step is rate determining and it is endothermic |
| Answer» Correct Answer - C | |
| 645. |
`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: Select the correct statement (s) about the graph 1:A. first step is rate determining and it is endothermicB. first step is rate determining and it is exothermicC. second step is rate determining and it is exothermicD. second step is rate determining and it is endothermic |
| Answer» Correct Answer - A | |
| 646. |
Match the following |
| Answer» Correct Answer - A::B::C::D | |
| 647. |
`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: `S^(N^(1))` reaction is :A. single step reactionB. two step reactionC. a reaction involving free radical intermediateD. a reaction involving carbocation intermediate |
| Answer» Correct Answer - D | |
| 648. |
Which of the following is used to replace halogen atom from chlorobenzene by CN?A. HCNB. AgCNC. CuCND. `CH_(3)-CN` |
| Answer» Correct Answer - C | |
| 649. |
Free radical halogenation takes place in the presence of light or at high temperature (abov 773K.) Formation of halogen free radical intermediate takes place in first step called chain initiation step. `CI_(2)overset(hv)(to)2CI` This reaction is mainly given by those compound which have atleast one hydrogen atom present at `sp^(3)-`hybrid carbon. Reactivity of `sp^(3)-`hybrid carbon depends on the reactivity of reaction intermediate. The relative rate of formation of alkyl radicals by a chlorine radical is : `underset((5))("Tertiary") gt underset((3.8))("Secondary") gt underset((1))("Primary")` `" Percentage yield of the prodcut "=("Relative amount"xx100)/("Sum of relative amounts")` Relative amount = Number of hydrogen atoms on the respective carbon `xx` relative reactivity. NBS (N-bromo succinimide) is used for bromination at allylic and benzylic carbon, whereas `Br_(2)//hv` gives bromination at benzylic allylic and alkyl carbon. Select most reactive compound for chlorination in presence of light :A. B. C. D. |
| Answer» Correct Answer - C | |
| 650. |
Free radical halogenation takes place in the presence of light or at high temperature (abov 773K.) Formation of halogen free radical intermediate takes place in first step called chain initiation step. `CI_(2)overset(hv)(to)2CI` This reaction is mainly given by those compound which have atleast one hydrogen atom present at `sp^(3)-`hybrid carbon. Reactivity of `sp^(3)-`hybrid carbon depends on the reactivity of reaction intermediate. The relative rate of formation of alkyl radicals by a chlorine radical is : `underset((5))("Tertiary") gt underset((3.8))("Secondary") gt underset((1))("Primary")` `" Percentage yield of the prodcut "=("Relative amount"xx100)/("Sum of relative amounts")` Relative amount = Number of hydrogen atoms on the respective carbon `xx` relative reactivity. NBS (N-bromo succinimide) is used for bromination at allylic and benzylic carbon, whereas `Br_(2)//hv` gives bromination at benzylic allylic and alkyl carbon. Arrange decreasing order of reactivity of given compounds with NBS :(N-bromo succinimide) `I. C_(6)H_(5)-CH_(3)` `II.C_(6)H_(5)-CH_(2)-CH_(2)CH_(3)` `III. C_(6)H_(5)-CH_(2)-CH=CH_(2)` `IV. C_(6)H_(5)-underset(CH_(3))underset(|)(CH)-CH=CH_(2)` Select the correct answer from the codes given below Codes:A. `IV,III,I,II`B. `IV,III,II,I`C. `I,II,III,IV`D. `I,III,II,IV` |
| Answer» Correct Answer - B | |