94420 + Interview Questions in Chemistry in Class 12

1.	Alkyl halides react with Mg in dry ether to form
Answer» Magnesium halide GRIGNARD's reagent Alkene Alkyne Solution :`RX+Mg OVERSET("Ether")rarr UNDERSET("Grignard's reagent")(RMGX)`

Discussion

2.	Alkyl halides react with dialkyl copper reagents to give :
Answer» alkenes alkyl COPPER halides Alkanes alkenyl haildes Answer :C

Discussion

3.	Alkyl halides react with dialkyl copper lithium reagents to give
Answer» Alkenes Alkyl COPPER halides Alkanes Alkenyl halides Solution :`R_(2)CuLi+R'XtoR-R'+R-Cu+LiX`

Discussion

4.	Alkyl halides reactwithDiakyl copper reagents to give :
Answer» alkenyl haides ALKANES ALKYL copperhalides alkanes ANSWER :B

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5.	Alkyl halides on treatment with aqueous KOH give :
Answer» Acids Alcohols Aldehydes ALKANES SOLUTION :`RX+aq.KOHrarrROH` (ALCOHOL)

Discussion

6.	Alkyl halides on treatment with a suspension of Ag_2O moist in ether gives :
Answer» Alkanol Alkanal Alkanes Alkoxy alkane Answer :D

Discussion

7.	Alkyl halides + Mg rarr (G)overset(H_2O)rarr CH_3CH_2CH_3.The alkyl halide is :
Answer» ETHYL bromide n- PROPYL iodide isopropyl iodide both (b) and ( C ) are CORRECT Answer :D

Discussion

8.	Alkyl halides may be prepared by __________ halogenation of alkanes.
Answer» ANSWER :FREE RADICAL

Discussion

9.	Alkyl halides give cyanides with KCN but isocyanides with AgCN as the products. Why?
Answer» Solution :The cyanide ion is a resonance hybrid of the FOLLOWING structures : `barC-= N hArr barN -= C` It is CLEAR from the resonating structures that cyanide ion can attack the nucleophilic site through .C. as WELL as through .N.. Such a nucleophile which is capable of attacking through more than one site is called ambident nucleophile. KCN is predominantly ionic and therefore, both .C. and .N. atoms are free to donate electron pair. Since, C-C bond is relatively stronger than C-N bond, therefore, the attack occurs mostly through the carbon atom of the cyanide group forming alkyl cyanides as the major product. On the other hand, AgCN is predominantly covalent. Therefore, in this case only N atom is free to donate electron pair and the attack mostly occurs through the N-atom of the cyanide group forming alkyl isocyanides as the major product. THUS, `RX overset(KCN)to UNDERSET("Alkyl cyanide")(RCN)` (attack occurs through .C.) `RX overset(AgCN)to underset("Alkyl isocyanide")(R-NC)`(attack occurs through .N.)

Discussion

10.	Alkyl halides give alcohols on hydrolysis With:
Answer» aq.NaOH Alc.NaOH Both of these NONE of these Answer :A

Discussion

11.	Alkyl halides can participate in both S_(N^(1)) and S_(N^(2)) reactions depending upon their anture and conditions. The reactivity order in the three types of alkyl halides is the reverse in S_(N^(1)) reactions than what we observe in S_(N^(2)) reactions. Apart from that, there is inversion of configuration in case of alkyl halides when they participate in S_(N^(2)) reactions. on the other hand, partial or complete racemisation occurs in S_(N^(1)) reactions. Q. An optically active halide when allowed to react with CN^(-), gives a racemic mixture. the halide is most likely to be: primary
Answer» secondary TERTIARY none of these Solution :OPTICALLY active tertiary alkyl halides GIVE racemix mixture by PARTICIPATING in `S_(N^(1))` reactions.

Discussion

12.	Alkyl halides can participate in both S_(N^(1)) and S_(N^(2)) reactions depending upon their anture and conditions. The reactivity order in the three types of alkyl halides is the reverse in S_(N^(1)) reactions than what we observe in S_(N^(2)) reactions. Apart from that, there is inversion of configuration in case of alkyl halides when they participate in S_(N^(2)) reactions. on the other hand, partial or complete racemisation occurs in S_(N^(1)) reactions. Q. S_(N^(1)) reactions take place much more rapidly in polar solvents than in non-polar solvents. this is because of hydration of nucleophile.
Answer» by the electron rich oxygen atoms of solvent `(H_(2)O)` molecules. stabilisation of CARBOCATION y the electorn rich oxygen atoms LEADING to SOLVATION. both are correct. none is correct. Solution :Solvation of carbocation RESULTS in release of energy as well as increase in its stability.

Discussion

13.	An alkyl halide may be converted into an alkene by which of the following reaction?
Answer» ELECTROPHILIC substitution Nucleophilicaddition ELIMINATION reaction Hydrolysis Answer :C

Discussion

14.	Alkyl halides can be obtained by all methods except:
Answer» `CH_3 CH_2 OH +HCloverset(ZnCl_2) rarr` `CH_3 - CH_2 - CH_3 + Cl_2overset(u.v.light)rarr` `C_2H_5OH + NACL rarr` `CH_3 COOAg + Br_2overset(C Cl_4) rarr` ANSWER :C

Discussion

15.	Alkyl halides are_____reactive than haloarenes but_____reactive than_____towards nucleophilic substitute ion reactions.
Answer» SOLUTION :More, LESS, allyl/benzyl HALIDES.

Discussion

16.	Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ? Ethoxy ethane
Answer» SOLUTION :`CH_3-CH_2Br + CH_3CH_2ONa RARR CH_3CH_2OCH_2CH_3 + NABR`

Discussion

17.	Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ? Butane
Answer» SOLUTION :`CH_3-CH_2Br + 2NA + BrCH_2 OVERSET(dry ether)RARR CH_3-CH_2-CH_2-CH_3 + 2NaBr`

Discussion

18.	Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ? Ethanol
Answer» SOLUTION :

Discussion

19.	Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ?Ethene
Answer» SOLUTION :

Discussion

20.	Alkyl halides are prepares from alcohols by treating with
Answer» <P>`HCl+ZnCl_(2)` Red `P+Br_(2)` `H_(2)SO_(4)+KI` All of the above Solution :(A) `R-OH overset(HCl)underset(ZnCl_(2))RARR R-Cl+H_(2)O` (B) `R-OH overset(" Red P ")underset(Br_(2))rarr R-Br+H_(3)PO_(3)`

Discussion

21.	Alkyl halides are prepared from alcohols by treating with
Answer» `HCl+ZnCl_(2)` Red `P+Br_(2)` `H_(2)SO_(4)+KI` All the above Solution :`H_(2)SO_(4)+KI` produces `I_(2)` but does not produce HI and HENCE does not react with alcohols to form alkyl IODIDES. Thus, OPTION (a) and (b) are CORRECT.

Discussion

22.	Alkyl halides are prepared from alcohol by treating with :
Answer» `HCl+ZnCl_(2)` `H_(2)SO_(4)+KI` `NaCl+H_(2)SO_(4)` NONE of these. Answer :A

Discussion

23.	Alkyl halides are insoluble in ………
Answer» WATER BENZENE HEXANE TOLUENE ANSWER :A

Discussion

24.	Alkyl halides are formed when thionyl chloride and _____ are refluxed in presence of pyridine. The order of reactivity (3^(@)gt2^(@)gt1^(@)) is due to +1 effect of the alkyl group which____ the polarity of C-X bond.
Answer» ACIDS, decreases alcohols, increases aldehydes, changes ketones, decreases Answer :B

Discussion

25.	Alkyl halides are almost insoluble in water because
Answer» They are covalent COMPOUNDS They have low POLARITY They do not FORM hydrogen BONDS with water They have tetrahedral geometry Answer :C

Discussion

26.	Alkyl halides are :
Answer» Monohalogen derivatives of alkanes Dihalogen derivatives of alkanes Trihalogen derivatives of alkanes Tetrahlogen derivatives of alkanes Solution :Alkyl halides are monohalogen derivatives of alkanes . They are derived from alkanes by the replacement of one or more HYDROGEN atom with the correspnding by the replacement of one or more hydrogen atom with the corresponding number of HALOGEN atoms. Tjhey are represented by general FORMULA `C_(N)H_(2n+1)X`

Discussion

27.	Alkyl halide reacts with lithium aluminium hydride to give alkane. Name the attacking reagent which will bring out this change.
Answer» Solution :The ATTACKING reagent obtained from LITHIUM aluminium hydride is `H^(-)`(hydride ION).

Discussion

28.	Alkyl halide on heating with alcoholic solution of silver salt of a carboxylic acid gives
Answer» Acid Alkane Esters Alcohols ANSWER :C

Discussion

29.	Alkyl halide (RBr) on treatment with KCN followed by reduction leads to formation of :
Answer» `RNH_2` `RCH_2NH_2` `RH + NH_3` `RCH_3 + N_2` ANSWER :B

Discussion

30.	Alkyl halide is obtained from alcohol on treating with
Answer» `PCI_(5)` `SOCl_(2)` `Cl_(2)` `PCl_(3)` SOLUTION :`R- OH UNDERSET(DELTA)overset(PCI_(5))to R-Cl+POCl_(3)+HCl` `3R-OHunderset(Delta)overset(PCI_(5))to 3R-Cl+H_(3)PO_(3)` `3R-OHunderset(Delta)overset(SOCl_(2))to R-Cl+SO_(2)+HCl`

Discussion

31.	Alkyl halide on heating with alcoholic solution of silver salt of a carboxylic acid gives :
Answer» ALCOHOLS Esters Acid Alkane Answer :B

Discussion

32.	Alkyl halide is immiscible with water. Explain.
Answer» Solution :ALKYL HALIDE is polar and it is insoluble in WATER because alkyl halide is not ABLE to form HYDROGEN bonds with water.

Discussion

33.	Alkyl halide having lowest b.pt is :
Answer» `CH_(2)H_(5)F` `CH_(2)H_(5)I` `CH_(2)H_(5)CL` `CH_(2)H_(5)Br` Answer :A

Discussion

34.	Alkyl halide can be converted into alkene by :
Answer» Nucleophilic SUBSTITUTION REACTION ELIMINATION reaction Both nucleophilic substitution and elimination reaction Rearrangement Answer :2

Discussion

35.	Alkyl halide exhibit
Answer» optical ISOMERISM poistion is CHAIN isomerism all of the above Solution :2-chloro butane SHOWS optical isomerism, 1-chloro butane and 2-chloro butane are position iomers. 1-chloro butane and 1-chloro2-methyl PROPANE are chain isomers.

Discussion

36.	Alkyl halide can be obtained from alkane or alkene by reaction with
Answer» HBr HCl `PCl_(5)` `Cl_(2)` Solution :`PCl_(5)` is used to PREPARE alkyl halides from alcohols.

Discussion

37.	Alkyl halide are insoluble in water, even though they are ploar-why?
Answer» Solution :Polar molecules of haloalkanes `(overset(delta+)(R)-overset(delta-)(X))`are held together by dipole-dipole attactions. On the contrary, water molecules remain associated through intermolecular hydrogen bonding. However, ALKYL HALIDE molecules are unable to FORM hydrogen bonds with water molecules. so, alkyl halides are insoluble in water. This can be interpreted alternatively as follows. for a haloalkane to dissolve in water, energy is required to overcome the dipole-dipole attracitons of haloalkanes and the BREAK the hydrogen bonds of water molecules. Such an amount of energy is not released when dipole-dipole attractions are set up between haloalkane and water molecules. Therefore, alkyl halides are practically insoluble in water.

Discussion

38.	Alkyl halide are-
Answer» MONO HALOGEN derivatives of alkanes Trihalogen derivatives of alkanes DI halogen derivatives of alkanes Tetra halogen derivatives of alkanes Answer :A

Discussion

39.	Alkyl halide and silver nitrite produces.
Answer» silver OXIDE nitroparaffins dinitroparaffins alkylnitrite Answer :B

Discussion

40.	Alkyl hailde when heated with alcoholic ammonia in a sealed tube, form :
Answer» primary AMINE a MIXTURE of primary and secondary amines a mixture of primary , secondary and TERTIARY amines a mixture of primary, secondary and tertiary amines TOGETHER with a quaternary salt. Answer :D

Discussion

41.	Alkyl fluorides are synthesised by heating an alkyl chloride/bromide in present of _____ or _____
Answer» `CaF_(2)` `CoF_(2)` `Hg_(2)F_(2)` `NaF` Solution :Only transition metal fluorides such as `CoF_(2) and Hg_(2)F_(2)` REACT with alkyl chloride/bromide to form alkyl fluorides. Alkali metal fluoride (NaF0 and alkaline EARTH metal fluorides do not react to form alkyl fluorides. Thus, option (B) and (c) are CORRECT.

Discussion

42.	Alkyl ethylamine is heated with chloroform and alcoholic KOH, a compound with offensive smell is formed. This compound is :
Answer» WILLIAMSON SYNTHESIS Mendius reaction Cannizzaro reaction Wurtz reaction Answer :B

Discussion

43.	Alkyl Fluorides are prepared by ……
Answer» FINKELSTEIN REACTION Hunsdiecker reaction WURTZ reaction SWARTZ reaction ANSWER :D

Discussion

44.	Alkyl cyanides undergo Stephen reduction to produce
Answer» Aldehyde Secondary amine Primary amine Amide Solution :When a solution of alkyl cyanides in ether is reduced with stannous chloride and hydrochloric acid at room TEMPERATURE, imine hydrochloric is obtained which on subsequent hydrolysis with boiling water, FORMS an aldehyde (Stepthen's reduction). `R-C-=Nunderset(2(H))OVERSET(SnCl_(2)//HCL)rarrRCH=NH.HCloverset(H_(2)O)rarrRCHO`

Discussion

45.	Alkyl fluorides are synthesised by alkyl chloride / bromide in presence of …….. or ……… .
Answer» `CaF_(2)` `CoF_(2)` `H_(g_(2))F_(2)` NaF Solution :`R-X OVERSET(A_(g))F" OR "Hg_(2)F_(2)" OR "CoF_(2))rarr R-F+AgX` `(X=Cl, Br)`

Discussion

46.	Alkyl cyanides have underline("lower ")boiling points than the isomeric isocyanides.
Answer» SOLUTION :ALKYL CYANIDES have HIGHER boiling point than the isomeric ISOCYANIDES.

Discussion

47.	Alkyl cyanides areunderline(" as poisonous as KCN").
Answer» SOLUTION :ALKYL CYANIDES are not as POISONOUS as KCN.

Discussion

48.	Alkyl cyanide on reduction with LiAlH_4 ether gives,
Answer» AMINE tertiary amine primary amine `2^(@)` amine Answer :C

Discussion

49.	Alkylcyanide(acetonitrile ) onreductionproduce
Answer» `1^(@)` amine `3^(@)` amine `2^(@)` amine quaternarysalt SOLUTION :`R-CN + 4[H]OVERSET( " Reduction ") (to)R- CH_(2) NH_(2)`

Discussion

50.	Alkyl chlorides on treatment with Nal in dry acetone gives alkyl iodides. What is this reaction known as ?
Answer» SOLUTION :FINKELSTEIN REACTION

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Alkyl halides react with Mg in dry ether to form

Alkyl halides react with dialkyl copper reagents to give :

Alkyl halides react with dialkyl copper lithium reagents to give

Alkyl halides reactwithDiakyl copper reagents to give :

Alkyl halides on treatment with aqueous KOH give :

Alkyl halides on treatment with a suspension of Ag_2O moist in ether gives :

Alkyl halides + Mg rarr (G)overset(H_2O)rarr CH_3CH_2CH_3.The alkyl halide is :

Alkyl halides may be prepared by __________ halogenation of alkanes.

Alkyl halides give cyanides with KCN but isocyanides with AgCN as the products. Why?

Alkyl halides give alcohols on hydrolysis With:

An alkyl halide may be converted into an alkene by which of the following reaction?

Alkyl halides can be obtained by all methods except:

Alkyl halides are_____reactive than haloarenes but_____reactive than_____towards nucleophilic substitute ion reactions.

Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ? Ethoxy ethane

Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ? Butane

Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ? Ethanol

Alkyl halides are the starting materials for the synthesis of a number of organic compounds. How is the following compound obtained from the alkylhalid CH_3-CH_2-Br ?Ethene

Alkyl halides are prepares from alcohols by treating with

Alkyl halides are prepared from alcohols by treating with

Alkyl halides are prepared from alcohol by treating with :

Alkyl halides are insoluble in ………

Alkyl halides are formed when thionyl chloride and _____ are refluxed in presence of pyridine. The order of reactivity (3^(@)gt2^(@)gt1^(@)) is due to +1 effect of the alkyl group which____ the polarity of C-X bond.

Alkyl halides are almost insoluble in water because

Alkyl halides are :

Alkyl halide reacts with lithium aluminium hydride to give alkane. Name the attacking reagent which will bring out this change.

Alkyl halide on heating with alcoholic solution of silver salt of a carboxylic acid gives

Alkyl halide (RBr) on treatment with KCN followed by reduction leads to formation of :

Alkyl halide is obtained from alcohol on treating with

Alkyl halide on heating with alcoholic solution of silver salt of a carboxylic acid gives :

Alkyl halide is immiscible with water. Explain.

Alkyl halide having lowest b.pt is :

Alkyl halide can be converted into alkene by :

Alkyl halide exhibit

Alkyl halide can be obtained from alkane or alkene by reaction with

Alkyl halide are insoluble in water, even though they are ploar-why?

Alkyl halide are-

Alkyl halide and silver nitrite produces.

Alkyl hailde when heated with alcoholic ammonia in a sealed tube, form :

Alkyl fluorides are synthesised by heating an alkyl chloride/bromide in present of _____ or _____

Alkyl ethylamine is heated with chloroform and alcoholic KOH, a compound with offensive smell is formed. This compound is :

Alkyl Fluorides are prepared by ……

Alkyl cyanides undergo Stephen reduction to produce

Alkyl fluorides are synthesised by alkyl chloride / bromide in presence of …….. or ……… .

Alkyl cyanides have underline("lower ")boiling points than the isomeric isocyanides.

Alkyl cyanides areunderline(" as poisonous as KCN").

Alkyl cyanide on reduction with LiAlH_4 ether gives,

Alkylcyanide(acetonitrile ) onreductionproduce

Alkyl chlorides on treatment with Nal in dry acetone gives alkyl iodides. What is this reaction known as ?

Alkyl halides are___reactive than haloarenes but_reactive than___towards nucleophilic substitute ion reactions.

Alkyl halides are formed when thionyl chloride and _ are refluxed in presence of pyridine. The order of reactivity (3^(@)gt2^(@)gt1^(@)) is due to +1 effect of the alkyl group which the polarity of C-X bond.

Alkyl fluorides are synthesised by heating an alkyl chloride/bromide in present of _ or _