52671 + Interview Questions in Chemistry in Class 11

1.	Alkylhalides have polar C-X bond and undergo nucleophilic substitution reactions. These give a variety of products with nucleophiles such as -OH, -OR, -NH_(2), -CN, -NC, -NO_(2), -ONO, RCOO^(-), etc. They undergo mainly two types of nucleophilic substitution reactions, S_(N)1 and S_(N)2. S_(N)1 reactions are two steps reactions which proceed through the formation of carbocations while S_(N)2 reactions are one step reaction which proceeds through the formation of transition state. The stability of carbocation and transition state determine the reactivity of alkyl halides. Write the main products A and B in the following reaction. A overset(KNO_(2))larr CH_(3)CH_(2)Br overset(AgNO_(2))to B.
Answer» SOLUTION :A: `CH_(3)CH_(2)-O-N=O` (ETHYL nitrite) B: `CH_(3)CH_(2)NO_(2)` (NITROETHANE)

Discussion

2.	Alkylation of phenoxide anion with allyl chloride gives
Answer» Phenyl allyl p-Allyl phenol o-Allyl phenol m-Allyl phenol Solution :PHENOXIDEION is an ambident ANION with NEGATIVE charge on both oxygen and ortho carbon atom of the ring. Attack by oxygen gives ether, attack by the orthocarbanion gives o-allyl phenol.

Discussion

3.	Alkyl halides undergo nucleophilic substitution reactions in which halogen atom is replaced by other atom. RX + Nu:^(-) to Nu-R + X^(-) These reactions follow S_(N)1 and S_(N)2 type mechanism, in which S_(N)1 takes place in two steps while S_(N)2 takes place in single step. Due to their tendency to undergo substitution by a large number of nucleophiles, they form a variety of products. In which of the following pairs, the first compound is better S_(N)2 substrate ?
Answer» 1-bromo-1-methyl cyclohexane, CYCLOHEXYL BROMIDE 1-iodo-2, 2-dimethyl propane, ISOPROPYL iodide 2, 2,-dimethyl-1-chlorobutane, 2-chloro butane isopropyl bromide, 2-bromobutane Answer :D

Discussion

4.	Alkyl halides undergo nucleophilic substitution reactions in which halogen atom is replaced by other atom. RX + Nu:^(-) to Nu-R + X^(-) These reactions follow S_(N)1 and S_(N)2 type mechanism, in which S_(N)1 takes place in two steps while S_(N)2 takes place in single step. Due to their tendency to undergo substitution by a large number of nucleophiles, they form a variety of products. In which of the following pairs, the first nucleophile is stronger?
Answer» `Cl^(-), I^(-)` `CH_(3)OH, CH_(3)S^(-)` `(CH_(3)CH_(2))_(2)NH, (CH_(3)CH_(2))_(3)N` `(CH_(3))_(2)O, (CH_(3))_(3)N` ANSWER :C

Discussion

5.	Alkyl halides undergo nucleophilic substitution reactions in which halogen atom is replaced by other atom. RX + Nu:^(-) to Nu-R + X^(-) These reactions follow S_(N)1 and S_(N)2 type mechanism, in which S_(N)1 takes place in two steps while S_(N)2 takes place in single step. Due to their tendency to undergo substitution by a large number of nucleophiles, they form a variety of products. Which of the following is least reactive towards S_(N)2 mechanism ?
Answer» `(CH_(3))_(2)CHCH_(2)BR` `(CH_(3))_(3)C CH_(2)Br` `CH_(3)CH_(2)Br` `(CH_(3))_(2)CHBr` Answer :B

Discussion

6.	Alkyl halides react with dialkyl copper reagent to give
Answer» ALKYL COPPER halides Alkenes Alkenyl halides ALKANES SOLUTION :Alkanes PREPARATIONS

Discussion

7.	Alkylhalides onreductionwiththe Zn-Cucoupleand alcohol, givecorrespondingalkanes . Theorderof reactivityof alkylhalidesthereactiionis __________.
Answer» R-ClgtR-BrgtR-I R-BrgtR-ClgtR-I R-ClgtR-IgtR-Br R-IgtR-BrgtR-Cl Answer :D

Discussion

8.	Alkyl halides can be obtained by all methods except :
Answer» `CH_(3)CH_(2)OH+HCl//ZnCl_(2)to` `CH_(3)-CH_(2)-CH_(3)-CH_(2)overset(Cl_(2)//UVlight)to` `C_(5)H_(5)OH +NaCl to` `CH_(3)COOAg+Br//C Cl_(4)to` SOLUTION :

Discussion

9.	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

10.	Alkoxides of beryllium [Be(OR)_(2)]_(6) usually have associated strutures with both mu_(2) - bridging and terminal OR groups. For example [Be(OCH_(3))_(2)]_(6) is a high polymer insoluble in hydrocarbon solvents. On the other hand, tertiary - butoxy derivative is less condensed being only a trimer [Be(O-t-Bu)_(2)]_(3) The vapour phase, BeCI_(2) is
Answer» two coordinate with lienar STRUCTURE three coordinate with PLANAR triangular structure four coordinate with regular tetrahedral structure four coordinate with irregular tetrahedral POLYMERIC structure Solution :In vapour state `BeCI_(2)` is three coordinate with plannar triangular structure

Discussion

11.	Alkoxides of beryllium [Be(OR)_(2)]_(6) usually have associated strutures with both mu_(2) - bridging and terminal OR groups. For example [Be(OCH_(3))_(2)]_(6) is a high polymer insoluble in hydrocarbon solvents. On the other hand, tertiary - butoxy derivative is less condensed being only a trimer [Be(O-t-Bu)_(2)]_(3)The C - Be - C angle [Be(CH_(3))_(2)]_(n) is
Answer» Equal to CI - Be - C angle in `[Be(CI_(2))]_(n)` Less than CI - Be - C angle in `[Be(CI_(2))]_(n)` Greater than the CI - Be - C angle in `[Be(CI_(2))]_(n)` NO REACTION to CI - Be - C angle in `[Be(CI_(2))]_(n)` Solution :The C - Be - C angle in `[Be (CH_(3))_(2)]_(n)` is less than CI - Be - C angle in `[Be (CI_(2))]_(n)` DUE to electronegative DIFFERENCE

Discussion

12.	Alkoxides of beryllium [Be(OR)_(2)]_(6) usually have associated strutures with both mu_(2) - bridging and terminal OR groups. For example [Be(OCH_(3))_(2)]_(6) is a high polymer insoluble in hydrocarbon solvents. On the other hand, tertiary - butoxy derivative is less condensed being only a trimer [Be(O-t-Bu)_(2)]_(3) With bulky alkoxide groups the beryllium compound exists as monomers which have
Answer» Linear structure with `180^(@)` BOND angle Trigonal PLANAR structure with `120^(@)` bond angle Tetrahedral structure with `190^(@)28^(3)` bond angle Distorted tetrahedral structure with more than `109^(@)28^(1)` in interal C - Be - C bond Solution :Beryllium compounds which exists as MONOMERS have linear structures with bond angle `180^(@)C`

Discussion

13.	Alkenes usually show which type of reaction
Answer» ADDITION Substitution Elimination Superposition Solution :Alkenes are UNSATURATED HYDROCARBON having double BOND so generally gives addition REACTION.

Discussion

14.	Alkenes undergo electrophilic addition with many reagents like HX, H_2O, HOCI etc. Except in the case of addition of X_2^(-) in other additions carbocation is formed as intermediate. The rate of such reactions depends on the stability of carbocation. Rearrangements and ring expansion are also common in such reactions. Propene on reaction with HI in presence of peroxide will give
Answer» 2-iodo PROPANE 1-iodopropane Both (a) & (b) none Solution :Peroxide EFFECT will not be present in HI

Discussion

15.	Alkenes undergo electrophilic addition with many reagents like HX, H_2O, HOCI etc. Except in the case of addition of X_2^(-) in other additions carbocation is formed as intermediate. The rate of such reactions depends on the stability of carbocation. Rearrangements and ring expansion are also common in such reactions. 1-methylcyclohex-1-ene is subjected to hydro-boration oxidation. The product is
Answer» Cis-2-methyl CYCLOHEXANOL Trans-2-methyl cyclohexanol 1-methyl cyclohexanol Both a & b Solution :HYDROBORATION OXIDATION is syn ADDITION

Discussion

16.	Alkenes undergo electrophilic addition with many reagents like HX, H_2O, HOCI etc. Except in the case of addition of X_2^(-) in other additions carbocation is formed as intermediate. The rate of such reactions depends on the stability of carbocation. Rearrangements and ring expansion are also common in such reactions. The correct order of reactivity of the following towards electrophilic addition is P) Vinyl chlorideQ) Pent-2-ene R) 3-methyl pent-2-eneS) 2,3-dimethyl but-2-ene
Answer» `P gt Q gt R gt S ` `S gt Q gt R gt P` `S gt R gt Q gt P` `R gt S gt Q gt P` Solution :P with `Cl` is least reactive as it exerts -I effect and destablises the intermediate carbocations FORMED AMONG others the carbocations formed from S, R, Q are Stability DECREASES a number of `alpha-H` atom decreases reactively decreases.

Discussion

17.	Alkenes are also known as
Answer» OLEFINS PARAFFINS ALIPHATIC SATURATED HYDROCARBONS Arenes Answer :A

Discussion

18.	Alkenes andalkynes are unsaturatedhydrocarbons and undergo electrophilic addition reactions. In alkenes, the addition occursin one step while in alkynes the addition occurs in twosteps. Alkenes show geometrical isomerism but alkynes do not. Alkynes are more acidic than alkenes which are more acidic than alkanes. Both alkenes and alkynes can be preparedby the electrolysisofsodium orpotassium salts of carboxylic acids. Which of the followingreacts with [Cu(NH_(3))_(2)]OH ? (i) But-1-yne(ii) But-2-yne(iii) But-1-ene
Answer» SOLUTION :(i) But-1-yne

Discussion

19.	Alkene R-CH=CH_(2) react with B_(2)H_(6) in the presence of H_(2)O_(2) to give
Answer» `R-UNDERSET(O)underset(\|\|)(C)-CH_(3)` `R-underset(OH)underset(\|)(CH)-underset(OH)underset(\|)(CH_(2))` `R-CH_(2)-CHO` `R-CH_(2)-CH_(2)-OH` Solution :`R-CH=CH_(2)underset(H_(2)O_(2)//OH^(-))overset(B_(2)H_(6))rarrR-CH_(2)-CH_(2)-OH` This is called as Hydroboration OXIDATION.

Discussion

20.	Alkene and alkyne gives electrophilic addition reaction, while benzene gives electrophilic substitution reaction. Give reason.
Answer» Solution :Due to resonance effect, wide spreaded delocalised `pi`-electron and aromaticity benzene RING is stable, so in benzene substitution reaction occurs easily with respect to addition reaction. Also BREAKING of `pi`-BOND in benzene is DIFFICULT so benzene gives substitution reaction. In substitution reaction, stability of benzene ring remains, sosubstitution reaction occurs easily in comparison to addition reaction. In alkene and alkyne, `pi`-bond easily breaks and hence, it favour the addition reaction.

Discussion

21.	Alkene can be converted in to oxirane by using which of the following
Answer» `O_2// AG ` MMPP (magnesium monoperoxy PHTHALATE) All of these Solution :In the presence of PERACIDS INSECTION takes PLACE.

Discussion

22.	Alkene(A) and (B) yield the same alcohol (C) on hydration. On vigorous oxidation with KMnO_4, (A) gives a carbonyl compound (D) and an acid (E) each containing four carbon atoms. On the other hand (B) gives an aicd (F) and a carbonyl compound (G), In (G), no two identical groups are attached to the same carbon atom. Give structures of (A) to (G) with proper resoning.
Answer» Solution :Akene (A) on OXIDATION gives a CARBONYL compound (D) and an acid (E). Each having for carbon atoms. THUS, the probable structure of (A) may be, `CH_3-CH_2underset(CH_3)underset(\|)C=CH-CH_2-CH_3` or `CH_3-CH_2-underset(CH_3)underset(\|)C=CH-underset(CH_3)underset(\|)CH-CH_3`. Alkene (B) gives an acid (F) and a carbonyl compound (G). Alkene (B) gives same alcohol on hydration and is ISOMERIC to (A) the carbonyl compound (G) has no carbon atom having two identical groups. Thus, the structure of (B) should be , `underset((B))(CH_3-CH=underset(CH_3)underset(\|)C-CH_2-CH_2-CH_2-CH_3)` The alkene (A) should also posses the corresponding structure, thus , structures of (A) is ,`underset((A))(CH_3-CH_2-underset(CH_3)underset(\|)C=CH-CH_2-CH_2-CH_3)` REACTIONS :

Discussion

23.	Alkanes with how many carbons are solids at rooms temperature
Answer» above `C_(17)` above `C_(10)` above `C_(8)` above `C_(4)` ANSWER :A

Discussion

24.	Alkanes with how many carbons are solids at room temperature
Answer» Above `C_(17)` Above `C_(10)` Above `C_8` Above `C_4` Solution :Above `C_(17)` are SOLIDS at ROOM temperature

Discussion

25.	Alkanes mainly undergo substitution reactions using the free - radical mechanism.
Answer» ANSWER :T

Discussion

26.	Alkanesmainlyexhibit ______reaction.
Answer» ANSWER :SUBSTITUTION

Discussion

27.	Alkanes having odd carbons cannot be prepared in A) Wurtz reaction B) Frankland reaction C) Kolbe's electrolysis D) Sabatier-sendersen reaction
Answer» B, C and D A, C and D A, B and D A, B and C Answer :B

Discussion

28.	Alkanes containing even number of carbon atoms possess higher melting points than those containing odd number of carbon atoms.
Answer» ANSWER :T

Discussion

29.	Why do alkynes not show geometrical isomerism ?
Answer» ANSWER :T

Discussion

30.	Alkanes can be prepared from sodium (or) potassium salts of carboxylic acid by using Kolbe'selectrolysis or decarboxylation with the help of sodalime. (NaOH and CaO)Sodium salt of carboxylic acid required to prepare Butane by Kolbe's electrolysis
Answer» SOLUTION :

Discussion

31.	Alkanes can be prepared from sodium (or) potassium salts of carboxylic acid by using Kolbe'selectrolysis or decarboxylation with the help of sodalime. (NaOH and CaO)Which of the Alkane cannot be prepared by Kolbe's electrolysis
Answer» `C_4H_(10)` `C_2H_6` `CH_4` `C_6H_(14)` SOLUTION :Methane cannot be prepared by Kolbe.s electrolysis SMALLEST ALKANE that can be prepared in ETHANE.

Discussion

32.	Alkanes burn with a smoky flame.
Answer» ANSWER :F

Discussion

33.	Alkanes are also referred to as............. and have the general formula …… .
Answer» SOLUTION :PARAFFINS, `C_nH_(2N + 2)`

Discussion

34.	Alkane may be prepared from alkyl halide by Wurtz method where alkyl halide reacted with Na in presence of ether . 2R - X underset(Delta)overset("Ether")to R - R + 2NaX Which of the following compound is most reactive for Wurtz reaction ?
Answer» `CH_3-OVERSET(BR)overset(\|)CH-CH_3` `CH_3-UNDERSET(CH_3)underset(\|)overset(CH_3)overset(\|)C-Br` SOLUTION :

Discussion

35.	Alkane may be prepared from alkyl halide by Wurtz method where alkyl halide reacted with Na in presence of ether . 2R - X underset(Delta)overset("Ether")to R - R + 2NaX CH_3 - underset(CH_3)underset(\|) overset(CH_3)overset(\|)C-Br underset(Delta)overset("Na/ether")to Major product :
Answer» `CH_3-UNDERSET(CH_3)underset(\|)OVERSET(CH_3)overset(\|)C-underset(CH_3)underset(\|)overset(CH_3)overset(\|)C-CH_3` `CH_3-underset(CH_3)underset(\|)overset(CH_3)overset(\|)-CH_2CH_3` No REACTION SOLUTION :

Discussion

36.	CH_3 - CH_2 - Cl underset(Delta)overset("Na/ether")(to)which of the following products may not be formed
Answer» SOLUTION :`CH_4`

Discussion

37.	"Alkane compounds normally resist the oxidation", what it mean ?
Answer» Solution :Formation of oxidized product by DECOMPOSITION of C-H bond in ALKANE is not an easy process and HENCE we can CONSIDER alkane to resist the OXIDATION.

Discussion

38.	"Alkane compound resist the oxidation", so what is your opinion for the following reaction ? C_(4)H_(10(g)) + (13)/(2)O_(2(g)) rarr 4CO_(2(g)) + 5H_(2)O_((l))
Answer» Solution :The given REACTION is of combustion of butane. Combustion is also an oxidation reaction, so in this reaction also oxidation occur. The negativity of C (2.5) and H (2.1) in reactant `C_(4)H_(10)`, so negativity of carbon is more and so it possess negativestate, while in product `CO_(2)`, carbon possess +4 oxidation state. So in this reaction oxidation number of carbon INCREASES and so this reaction is of oxidation. "Combustion of all alkane is ultimately oxidation reaction only".

Discussion

39.	Alkane (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted into another alkane containing less than four carbon atoms. (A) is
Answer» Solution :(i)Let A beR-H, on BROMINATION , it will give R-Br `underset"Alkane (A)" (R-H)+ Br_2 overset"hv"to underset"Alkyl bromide"(R-Br)+HBR ` (ii)Now Wurtz reaction of alkyl bromide gives alkane (B) `R-Br + 2Na + Br-R overset"Heat"to underset"Alkane (B)"(R-R) + 2NaBr` (iii)SINCE alkane (B) contains less than four carbon atoms, therefore , R can have only one carbon atom. In other words , R is `CH_3` and hence alkane (A) is `CH_4` All the reactions INVOLVED here are : `underset"Methane (A)"(CH_4)underset"-HBr"overset(Br_2)to underset"Methyl bromide "(CH_3Br) underset"(Wurtz reaction)"overset"Na, Dry ether"to underset"(Less than 4 carbon atoms )"(CH_3-CH_3)`

Discussion

40.	Alkaline KMnO_(4) solution converts acetylene into
Answer» ACETALDEHYDE OXALIC acid Acetic aci Glycol Answer :C

Discussion

41.	Alkaline hydrolysis of urea with dill. NaOH gives
Answer» BIURET and ammonia Ammonia and SODIUM carbonate Nitrogen and sodium carbonate Ammonia and cyanuric acid Solution :

Discussion

42.	Alkaline earth metals produce ....... color on solubilizing in ammonia solution.
Answer» Brown Light green Dark blue Light RED ANSWER :C

Discussion

43.	Alkaline earth metals form basic hydroxides. The metal hydroxide which is most basic is ___________
Answer» `MG(OH)_2` `Ca(OH)_2` `SR(OH)_2` `Ba(OH)_2` Answer :D

Discussion

44.	Alkaline earth metals form halides of the type MX_(2) Which is false about them ?
Answer» They can be PREPARED by the direct reaction of METAL and halogens bertylliumhalidesare covalentwhilethe halidesof otherelementsare ionic Beryllium halides are covalent from `BeX_(2)` to `BaX_(2)` EXCEPT`BeF_2`the solubilityof otherhalidesincreases from ` BeX_2 "to" BaX_2` Answer :D

Discussion

45.	Alkaline earth metals exhibit +2 oxidation state in aqueous solution due to
Answer» SMALL SIZE of metal atoms their hydration energies being HIGHER than second IONISATION potential their hydration energy being less than second ionisation potential their LOW second ionisation potential Answer :B

Discussion

46.	Alkalineearthmetalsbelong to the
Answer» <P>S- BLOCKIN PERIODICTABLE p - blockinperiodictable d- blockin periodictable ANSWER :A

Discussion

47.	Alkaline earth metals are
Answer» Monovalent Divalent Trivalent Zerovalent Answer :B

Discussion

48.	Alkaline earth metals always form divalent cations even through their second ionization enthalpies are almost double than their first ionization enthalpies . Explain .
Answer» Solution :In the solid state , higher enthalpy of lattice formationby `M^(2+)` ions (as compared to `M^(+)`ions) more than compensates the higher SECOND ionization enthalpies of METALS and in AQUEOUS solution , higher enthalpy of HYDRATION of `M^(2+)` ions (as compared to `M^(+)` ions) more than compensates the higher second ionization enthalpy

Discussion

49.	_______alkaline earth metal is not readily attacked by acids
Answer» SOLUTION :BERYLLIUM

Discussion

50.	Alkaline earth metal having least melting point is
Answer» `Be` `MG` `CA` `BA` ANSWER :B

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Alkylation of phenoxide anion with allyl chloride gives

Alkyl halides react with dialkyl copper reagent to give

Alkylhalides onreductionwiththe Zn-Cucoupleand alcohol, givecorrespondingalkanes . Theorderof reactivityof alkylhalidesthereactiionis __________.

Alkyl halides can be obtained by all methods except :

Alkyl halides are prepared from alcohol by treating with:

Alkenes usually show which type of reaction

Alkenes are also known as

Alkene R-CH=CH_(2) react with B_(2)H_(6) in the presence of H_(2)O_(2) to give

Alkene and alkyne gives electrophilic addition reaction, while benzene gives electrophilic substitution reaction. Give reason.

Alkene can be converted in to oxirane by using which of the following

Alkanes with how many carbons are solids at rooms temperature

Alkanes with how many carbons are solids at room temperature

Alkanes mainly undergo substitution reactions using the free - radical mechanism.

Alkanesmainlyexhibit ______reaction.

Alkanes having odd carbons cannot be prepared in A) Wurtz reaction B) Frankland reaction C) Kolbe's electrolysis D) Sabatier-sendersen reaction

Alkanes containing even number of carbon atoms possess higher melting points than those containing odd number of carbon atoms.

Why do alkynes not show geometrical isomerism ?

Alkanes can be prepared from sodium (or) potassium salts of carboxylic acid by using Kolbe'selectrolysis or decarboxylation with the help of sodalime. (NaOH and CaO)Sodium salt of carboxylic acid required to prepare Butane by Kolbe's electrolysis

Alkanes can be prepared from sodium (or) potassium salts of carboxylic acid by using Kolbe'selectrolysis or decarboxylation with the help of sodalime. (NaOH and CaO)Which of the Alkane cannot be prepared by Kolbe's electrolysis

Alkanes burn with a smoky flame.

Alkanes are also referred to as............. and have the general formula …… .

Alkane may be prepared from alkyl halide by Wurtz method where alkyl halide reacted with Na in presence of ether . 2R - X underset(Delta)overset("Ether")to R - R + 2NaX Which of the following compound is most reactive for Wurtz reaction ?

Alkane may be prepared from alkyl halide by Wurtz method where alkyl halide reacted with Na in presence of ether . 2R - X underset(Delta)overset("Ether")to R - R + 2NaX CH_3 - underset(CH_3)underset(|) overset(CH_3)overset(|)C-Br underset(Delta)overset("Na/ether")to Major product :

CH_3 - CH_2 - Cl underset(Delta)overset("Na/ether")(to)which of the following products may not be formed

"Alkane compounds normally resist the oxidation", what it mean ?

"Alkane compound resist the oxidation", so what is your opinion for the following reaction ? C_(4)H_(10(g)) + (13)/(2)O_(2(g)) rarr 4CO_(2(g)) + 5H_(2)O_((l))

Alkane (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted into another alkane containing less than four carbon atoms. (A) is

Alkaline KMnO_(4) solution converts acetylene into

Alkaline hydrolysis of urea with dill. NaOH gives

Alkaline earth metals produce ....... color on solubilizing in ammonia solution.

Alkaline earth metals form basic hydroxides. The metal hydroxide which is most basic is ___________

Alkaline earth metals form halides of the type MX_(2) Which is false about them ?

Alkaline earth metals exhibit +2 oxidation state in aqueous solution due to

Alkalineearthmetalsbelong to the

Alkaline earth metals are

Alkaline earth metals always form divalent cations even through their second ionization enthalpies are almost double than their first ionization enthalpies . Explain .

_______alkaline earth metal is not readily attacked by acids

Alkaline earth metal having least melting point is