Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

An aqueous solution contains an unknown concentration of Ba^(+). When 50 mL of 1 M solution of Na_(2)SO_(4) is added, BaSO_(4) is 1xx10^(-10). What is the original concentration of Ba^(2+)?

Answer»

`5xx10^(-9)M`
`2xx10^(-9)M`
`1.1xx10^(-9)M`
`1.0xx10^(M)`

Solution :As 50 mL of 1 M `Na_(2)SO_(4)` solution are present in 500 mL of final solution, this means that 1 M `Na_(2)SO_(4)` has been diluted 10 TIMES. Hence, Conc. Of `[SO_(4)^(2-)]` in final solution `= (1)/(10) M = 0.1 M`
`K_(sp) ` of `BaSO_(4) = 10^(-10)`
`:. [BA^(2+)][SO_(4)^(2-)]=10^(-10)`
`[Ba^(2+)][0.1]=10^(-10)`
or `[Ba^(2+)]=10^(-9)M`
i.e., conc. of `Ba^(2+)` ions in final solution `=10^(-9)`M
Volume of final solution = 500 mL
Volume of ORIGINAL solution = 500 - 50 = 490 mL
Applying `underset("(INITIAL)") M_(1)V_(1)=underset("(Final)")M_(2)V_(2)`
`M_(1)xx900=(10^(-9))(500)`
or, `M_(1)=1.11xx10^(-9)M`
2.

An aqueous solution contains 10% ammonia by mass and has a densityof 0.99 g cm^(-3) . Calculate hydroxyl and hydrogen ion concentration in this solution . K_(a)for NH_(4)^(+)=5.0xx10^(-10).

Answer»

Solution :10% ammonia by mass means 10 g `NH_(3)` are present in 100 g of the solution.
`:.` Molarity of the solution `=(10)/(17) xx (1)/(100//0.99)xx1000 = 5.82 M`
`{:(,NH_(3) ,+,H_(2)O,rarr,NH_(4)OH,hArr,NH_(4)^(+),+,OH^(-),),("Initial conc.",,,,,C "MOL" L^(-1),,,,,),("After dissociation",,,,,C-Calpha,,C alpha,,C alpha,),(,,,,,=C(1-alpha),,,,,):}`
`:. [OH^(-)] = C alpha = C SQRT((K_(b))/(C)) = sqrt(K_(b)C)= sqrt((K_(w))/(K_(a))xxC)=sqrt((10^(-14))/(5.0xx10^(-10))xx5.82)=1.079xx10^(-2)M(alpha = sqrt(K_(b)//C) and K_(a)xxK_(b)=K_(w))`
`:. [H^(+)]=(K_(w))/([OH^(-)]) = (10^(-14))/(1.079xx10^(-2))=0.9268xx10^(-12) M = 9.268xx10^(-13)M`
3.

An aqueous solution contains0.10 M H_(2)S" is "1.0 xx 10^(-7)" and that of " S^(2-) "ion from " HS^(-) "ions is " 1.2 xx 10^(-3) ," then the concentration of " S^(2-) " ions in aqueous solution is "

Answer»

` 5 xx 10^(-8)`
`3 xx 10^(-20)`
`6xx 10^(-21)`
`5xx 10^(-19)`

Solution :Given : (i) ` H_(2) S hArr HS^(-) + H^(+),`
`K_(a_(1)) = 1.0 xx 10^(-7)`
(II) `HS^(-) hArr S^(2-) + H^(+), K_(a_(2))= 1.2 xx 10^(-13)`
For the reaction , ` H_(2)S hArr 2 H^(+) + S^(2-)`
(obtained by adding (i) and (ii) )
`K_(a) = K_(a_(1)) xx K_(a_(2))`
` :. (1.0 xx 10^(-7)) (1.2 xx 10^(-13))= ([H^(+)]^(2) [S^(2-)])/([H_(2)S]) `
In presence of HCL, `[H^(+)]` are obtained mainly from HCl. Hence ,
` [H^(+)] = 0.20 M, [H_(2) S]= 0.1 M `
`:. 1.2 xx 10^(-20) = ((0.2 )^(2)[S^(2-)])/0.1`
or `[S^(2-)] = 3 xx 10^(20)`
4.

An aqueous solution contains 0.10 M H_2Sand 0.20 M HCl. If the equilibrium constants for the formation of HS^- from H_2S is 1.0 xx 10^(-7) and that of S^(2-)from HS^-ions is 1.2 xx 10^(-13)then the concentration of S^(2-) ions in aqueous solution is :

Answer»

`5 xx 10^(-8)`
`3 xx 10^(-20)`
`6 xx 10^(-21)`
`5 xx 10^(-19)`

Solution :
` therefore KA(iii) = ka(i) xx ka(ii)`
` = (1 xx 10^(-7) (1.2 xx 10^(-13))`
` = 1.2 xx 10^(-20)`
(iii) of ka (iii) = ([H^+][S^(2-)])/([H_2S])`
Where , `[H_2S] = 0.1 M, [H^+]= 0.2M = [HCl]`
` therefore 1.2 xx 10^(-20) = (0.2)^2 (S^(2-) ) // 0.1`
`therefore [S^(2-)] = (0.1 xx 1.2 xx 10^(-20))/((0.2)^2)`
` = 0.3 xx 10^(-20) = 3 xx 10^(-21)`
5.

An aqueous solution contains 0.10 M H2S and 0.20 M HCl. If the equilibrium constants for the formation of HS^(-)fromH_(2)S" is " 1.0 xx 10^(-7) " andthat of " S^(2-) " from " 4S^(-) " ionsis " 1.2 xx 10^(-13) ,then find the concentration of S^(-2) ions in aqueous solution

Answer»

Solution :`underset((0.1 - x))(H_(2)S(AQ.)) hArr underset((2x + 0.29))(2H^(+) )+ underset(x)(S^(2-) )`
`K_(a) = K_(a_(1)) xx K_(a_(2)) = 1.2 xx 10^(-20) `
`1.2 xx 10^(-20) = ((0.2)^(2-) [S^(2-)])/(0.1) , [S^(2-)] = 3 xx 10^(-20) `
6.

An aqueous solution containing 0.10 g KIO_(3) (formula weight =214.0) was treated with an excess of KI solution. The solution was acidified with HCl. The liberated iodine consumed 45.0 mL of thiosulphate solution to decolourise the blue starch-iodine complex. Calculate the molarity of the sodium thiosulphate solution.

Answer»


SOLUTION :`2KIO_(3)+10KI+12HCl to 12 KCl +6I_(2)+6H_(2)O`
[`2Na_(2)S_(2)O_(3)+I_(2) to 2NaI+Na_(2)S_(4)O_(6)]xx6`
`overlineul(underset(2"moles")(2KIO_(3))+10KI+underset(12"moles")(12Na_(2)S_(2)O_(3))+12HCl to 12KCl+12NaI+6Na_(2)S_(4)O_(6)+6H_(2)O)`
No. of moles of `KIO_(3)=(0.10)/(214)`
No. of moles of `Na_(2)S_(2)O_(3)` REQUIRED for `(0.10)/(214)` moles of `KIO_(3)`
`=(12)/(2)xx(0.10)/(214)=(0.60)/(214)`
Molarity of `Na_(2)S_(2)O_(3)=(0.6)/(214)xx(1000)/(45)=0.0623 M`
7.

An aqueous solution an unknown concentration of Ba^(2+) , When 50 mL of a 1 M solution of Na, S0, is added, BaSO_4 , just begins to precipitate. The final volume is 500 mL. The solubility product of BaSO_4is 1 xx 10^(-10). What is the original concentration of Ba^(2+)

Answer»

`5 xx 10^(-9) M`
`2 xx 10^(-9) M`
`1.1 xx 10^(-9) M`
`1.0 xx 10^(-10) M`

SOLUTION :`1.1 xx 10^(-9) M`
8.

An aqueous sodium hydroxide solution contains, 80ppm NaOH. If one ml of the solution is mixed with 99 ml water, the molarity of the resultant solution is x xx10^(-5) what is x? (assume d=gm/cc)

Answer»


SOLUTION :PPM = `(w_(1))/(w_(2))xx10^(6)=80`
`M=(w_(1))/(40xx((w_(2))/(1000)))(because w_(2)=V_("SOLN (mL)"))`
`=(w_(1))/(w_(2))XX(1000)/(40)=(80xx10^(-6)xx1000)/(40)=2xx10^(-3)M`
`M_(1)V_(1)=M_(2)V_(2)`
`1xx2xx10^(-3)=100xxM_(2)impliesM_(2)=2xx10^(-5)`
9.

An aqueous glucose solution contains 180 ppm glucose. If one .ml. of the solution is mixed with 99ml water, the molarity of the resultant solution is x xx10^(-y). What is y? (d=1 gm/cc)

Answer»


Solution :`(w_(1))/(w_(2))xx10^(6)=180(w_(2)=V_("sol.(ml)"))`
`M=(w_(1))/(180xx((w_(2))/(1000)))=(w_(1))/(w_(2))xx(10^(3))/(180)`
`=(180)/(10^(6))xx(10^(3))/(180)=10^(-3)M`
`M_(1)V_(1)=M_(2)V_(2)implies1xx10^(-3)=100xxM_(2)`
`M_(2)=10^(-5)`
10.

An aqeous solution contains 10% ammonia by mass and has density of 0.99 gm cm^(-3). The pH of this solution is [Ka of NH_(3) = 5 xx 10^(-10)M]

Answer»

`11.033`
`12.033`
`9.033`
`7.2033`

Solution :Given,
`("wt. of" NH_(3))/("wt. of solution") = (10)/(100)`
`100g` solution contains `10g NH_(3)`
`M_(NH_(3)) = ((10 xx 1000))/([17 xx (100//0.99)]) = 5.82`
`(':. V = ("mass")/("density"))`
Now,
`NH_(3) + H_(2)O rarr NH_(4)OH hArr NH_(4)^(+) + OH^(-)`
`"Before dissociation" ,1,0,0`
`"After dissociation",(1-Calpha),Calpha,Calpha`
`[OH^(-)] = C.alpha = Csqrt(((K_(b))/(C))) = SQRT((K_(b).C))`
`C = 5.82 M` and `K_(b) = K_(w)//K_(a)`
`= 10^(-14)//(5 xx 10^(-10)) = 2 xx 10^(-5)]`
`[OH^(-)] = sqrt([2 xx 10^(-5) xx 5.82]) = 1.07 xx 10^(-2) M`
`[H^(+)] = 10^(-14)//1.07 xx 10^(-2)`
`= 0.9268 xx 10^(-12) M`
`pH = - "log"[H^(+)] = - "log" 0.9268 xx 10^(-12) = 12.0330`.
11.

An antiseptic sold in the market

Answer»

CALGON
PERHYDROL
Hyperal
PERMUTIT

ANSWER :B
12.

An antifreeze solution is prepared for a laboratory experiment. In this solution 222.6g of ethylene glycol is dissolved in 200g of water. The density of resultant solution was found to be 1.072 "g mL"^(-1). Molal depression constant of water is "1.86 K kg mol"^(-1) and molar mass of ethylene glycol (C_(2)H_(6)O_(2)) is "62 g mol"^(-1). Freezing point of the solution will be :

Answer»

`-17.387^(@)C`
`-33.387^(@)C`
`-3.38^(@)C`
`-0.338^(@)C`

ANSWER :B
13.

An antifreeze solution is prepared for a laboratory experiment. In this solution 222.6g of ethylene glycol is dissolved in 200g of water. The density of resultant solution was found to be 1.072 "g mL"^(-1). Molal depression constant of water is "1.86 K kg mol"^(-1) and molar mass of ethylene glycol (C_(2)H_(6)O_(2)) is "62 g mol"^(-1). Molarity of solution is :

Answer»

0.911
9.11
17.95
1.795

Answer :B
14.

An antifreeze solution is prepared for a laboratory experiment. In this solution 222.6g of ethylene glycol is dissolved in 200g of water. The density of resultant solution was found to be 1.072 "g mL"^(-1). Molal depression constant of water is "1.86 K kg mol"^(-1) and molar mass of ethylene glycol (C_(2)H_(6)O_(2)) is "62 g mol"^(-1). Molality of solution is :

Answer»

17.95
0.1795
1.795
5.197

Answer :A
15.

An anhydride R'COOCOR on reduction with LiAlH_(4) will give

Answer»

`R'CH_(2)OH` and ROH
`RCH_(2)OH` and R'OH
`R'CH_(2)OH` and `RCH_(2)OH`
R'OH and ROH

Solution :`R'. CO. O. CO.R + 8[H] UNDERSET(-H_(2)O)overset(LiAlH_(4))rarr R'CH_(2)OH + RCH_(2)OH`
16.

An amount of solid NH_(4) HS is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm, pressure . Ammonium hydrogen sulphide decomposes to yield NH_(3) and H_(2) S gases in the flask . When the decomposition reaction reaches equilibrium the total pressure in the flask rises to 0.84 atm . The equilibrium constant for NH_(4) HS decomposition at this temperature is

Answer»

`0.30`
`0.18`
`0.17`
`0.11`

ANSWER :D
17.

An amorphous solid is :

Answer»

NACL
`CaF_2`
GLASS
CsCl

Answer :C
18.

An amorphous solid 'A' burns in air to form a gas 'B' which turns lime water milky. The gas is also produced as a by-product during roasting of sulphide ore. This gas decolourises acidified aqueous KMnO_(4) solution and reduces Fe^(3+)" to "Fe^(2+). Identify the solid ''A'' and the gas ''B'' and write the reactions involved.

Answer»

Solution :(i) Since gas 'B' is obtained as a by -product during roasting of sulphide, THEREFORE, gas 'B' must be `SO_(2)`.
`2ZnS+3O_(2)to2ZnO+2SO_(2)(B)`
(ii) Since gas 'B' is obtained when amorphous solid 'A' burns in air, therefore, amorphous solid 'A' must be sulphur, `S_(8)`.
`S_(8)(A)+8O_()to8S_(2)(B)`
(iii) Gas 'B' reduces acidified `KMnO_(4)` solution and reduces `FE^(3+)" to "Fe^(2+)` salts as shown below :
`{:underset("Purple")(2MnO_(4)^(-))+underset((B))5SO_(2)+2H_(2)Otounderset("COLOURLESS")(2Mn^(2+))+5SO_(4)^(2-)+4H^(+):}`
`{:underset(("Yellow"))(2Fe^(3+))+underset((B))SO_(2)+2H_(2)Otounderset(("Green"))(2Fe^(2+))+SO_(4)^(2-)+4H^(+):}`
Thus, solid 'A' = `S_(8)` and gas 'B' = `SO_(2)`.
19.

An amorphous is also called glassy material. Why ?

Answer»

SOLUTION :Glass is an amorphous solid. It is not a TRUE solid, because SILICATE units are IRREGULAR both in size and orientation.
20.

An amide is heated with a mixture of NaNO_(2)//HCl, the gas product is

Answer»

`N_(2)O`
`N_(2)`
`NH_(3)`
`O_(2)`

SOLUTION :`RCONH_(2) + HNO_(2) rarr RCOOH + N_(2) UARR + H_(2)O`
21.

An alpha – particle having kinetic energy 5 MeV falls on a Cu-foil. The shortest distance from the nucleus of Cu to which alpha - particle reaches is (Atomic no. of Cu = 29, K= 9xx10^9 Nm^2//C^2)

Answer»

`2.35xx10^(-13)` m
`1.67 XX 10^(-14) m`
`5.98 xx 10^(-15)`
`1.67 xx 10^(-16)` m

Solution :`K.E. = (K.Ze.2e)/(r)`
`r= (9xx10^9 xx 29xx 2xx1.6 xx 10^(-19)^2)/(5XX 1.6 xx 10^(-19) xx 10^(6))`
`r= (9xx10^9 xx 29 xx 2 xx 1.6 xx 10^(-19))/(5xx 10^6)`
`= 1.67 xx 10^(-14) m`
22.

An alpha-particle changes into a Helium atom. In the course of one year the volume of Helium collected from a sample of Radium was found to be 1.12 xx10^(-2)mL at STP. The number of alpha particles emitted by the sample of Radium in the same time is

Answer»

`6XX 10^(17)`
`3 xx 10^(17)`
`1.5 xx 10^(17)`
`1.2 xx 10^(18)`

Answer :B
23.

An alloy of copper and aluminium which has beautiful golden yellow colour is called "…………..".

Answer»


ANSWER :ALUMINIMUM BRONZE
24.

Analloycontatining1- 15%Mgand 85-99%Al is knownas ______ .

Answer»

ELEKTRON
MAGNALIUM
alnico
Duralumin

ANSWER :B
25.

An alkyne differs with an alkene when tested with A) Bromine water B) Tollen's reagent C) Baeyer's reagent

Answer»

A and C
B and C
A only
B only

Answer :D
26.

An alkyne combines with a conjugated diene of give an unconjugated cycloalkadiene. The most likely title of this reaction is

Answer»

SCHOTTEN Baumann reaction
Hofmann bromamide reaction
Pinacol-pinacolone REARRANGEMENT
Diels-Alder reaction

Solution :
27.

An alkylhalide with molecular formula C_(6)H_(13)Bron dehydro halogenation gave two isomeric alkenes Xand Y with molecular formula C_(6)H_(12) .On reductive ozonolysis , Xand Y gave four compounds CH_(3)COCH_(3), CH_(3)CHO, CH_(3)CH_(2)CHO and (CH_(3))_(2)CHCHO.Find the alkylhalide.

Answer»

Solution :`(i)` The alkyl halide with MOLECULAR FORMULA `C_(6)H_(13)BR` is bromohexane (`2`-"Bromo"`-2,3`-"dimethylbutane")
`(ii)` `C_(6)H_(13)Br` on dehydro halogenation gives two isomeric alkenes `2`,`3`- dimethyl-`1`-BUTENE `(X)` and `2`,`3`-dimethyl-`2`-butene`(Y)`
`H_(3)C-underset(CH_(3))underset(|)(C )H-overset(Br)overset(|)underset(CH_(3))underset(|)(C )-CH_(3) overset(."alc"KOH)(to)`
`(iii) X` and `Y` on reductive ozonolysis GAVE four compounds `CH_(3)COCH_(3)`, `CH_(3)CHO`, `CH_(3)CH_(2)CHO` and `(CH_(3))_(2)CHCHO`,
`(iv)` `X-2,3` dimethyl -`1`-butene
`Y-2,3` dimethyl -`2`-butene
28.

An alkyl halide (X) on reaction with ethanolic sodium hydroxide forms an alkene (Y) which on further reaction with HBr gives the same alkyl halide.The alkene (Y) on reaction with HBr/ peroxide followed by reaction with Hg metal followed by reaction with HCN produces an aldehyde (Z).Z is :

Answer»




ANSWER :B::C
29.

An alkyl halide , X, of formula C_6H_13Cl on treatment with potassium tertiary butoxide gives two isomeric alkenes X and Z (C_6H_12). Both alkenes on hydrogenation give 2,3-dimethylbutane. Predict the structures of X , Y and Z .

Answer»

SOLUTION :
30.

An alkyl halide with molecular formula C_(6)H_(13)Br on dehydrohalogenation gave two isomeric alkens X and Y with molecular formula C_(6)H_(12) on reductive ozonolysis X and Y gave fourcompounds CH_(3)COCH_(3)CH_(3)CHOCH_(3)CH_(2)CHO and (CH_(3))_(2) CHCHO find the alkyl halide

Answer»

Solution :`(i) C_(6) H_(13) Br ` is 3- Bromo -methylpentane.
`CH_(3)-underset(CH_(3))underset(|)(CH ) - underset(H)underset(|) overset(Br) overset(|)(C ) -CH_(3)`
(ii)3- Bromo-4methyl pentaneon dehydrogenation givetwoisomersx and yas FOLLOWS
`CH_(3)- underset(CH)(underset(|)overset( Br)overset(|)(C )- CH_(3) -CH_(3)`

Therefore `C_6H_(13) Br`is 3 Bromo-4-methylpentane
31.

An alkyl halide C_5H_11Br (A) reacts with ethanolic KOH to give an alkene 'B', which reacts with Br_2 to give a compound 'C', which on dehydrobromination gives an alkyne 'D'. On treatment with sodium metal in liquid ammonia , one mole of 'D' gives one mole of the sodium salt of 'D' and half a mole of hydrogen gas . complete hydrogenation of 'D' yields a straight chain alkane. Identify A,B, C and D .Give the reactions involved.

Answer»

Solution :The outline of reaction scheme involved in the given problem is
`underset"ALKYL halide (A)"(C_5H_11Br) overset"Alc. KOH"to underset"Alkene (B)"(C_5H_10) overset(Br_2//CS_2)to underset"(C )"(C_5H_10Br_2) underset"-2 HBR"overset"Alc. KOH"to underset"Alkyne (D)"(C_5H_8) overset(Na- liq. NH_3)to underset"Sod. Alkynide"(C_5H_7Na+1//2H_2)`
(i)SINCE 1 mole of alkyne 'D' reacts with 1 mole of Na in liquid `NH_3` to form half a mole of `H_2`, therefore, (D) is a terminal alkyne. This means that triple bond is at the end of the carbon chain. The two structures for alkyne (D) are either (I) or (II)
`underset"1-Pentyne (I)"(CH_3CH_2CH_2-C-=CH) " " underset"3-Methylbut-1-yne (II)"(CH_3-oversetoverset (CH_3)|CH-C-=CH)`
Since alkyne 'D' on complete hydrogenation yields a straight chain alkane, therefore , the alkyne (D) is a straight chain alkyne, i.e., alkyne (D) is 1-pentyne (I).
(ii)Since alkene (B) on reaction with `Br_2` forms a compound 'C' which one dehydrohalogenation gives the alkyne, i.e., 1-pentyne (D), therefore, (C ) MUST be 1,2-dibromopentane and alkene (B) must be 1-pentene .
(iii)Furthersince alkene (B), i.e., 1-pentene is obtained by dehydrogenation of alkyl halide with M.F. `C_5H_11Br`, therefore,alkyl halide (A) must be 1-bromopentane.
All the reactions involved in this question may now be explained as follows :
`underset"1-Bromopentane (A)"(CH_3CH_2CH_2CH_2CH_2Br) underset"-HBr"overset(Alc. KOH, DELTA)tounderset"1-Pentene (B)"(CH_3CH_2CH_2CH=CH_2) overset(Br_2 "in" Cs_2)tounderset"1,2-Dibromopentane (C )"(CH_3CH_2CH_2-overset2CHBr-overset1CH_2Br) underset"-2HBr " overset(Alc. KOH, Delta)tounderset"1-Pentyne (D)" (CH_3CH_2CH_2C-=CH) overset("Na in liq." NH_3)to underset"Sodium 1-pentynide"(CH_2CH_2CH_2C-=CNa +1//2H_2)`
Please not that alkyl halide (A) cannot be 2-bromopentane becausedehydrobromination of (A) would have given 2-pentane as the major product in accordance with Markovnikov's rule.
32.

An alkyl halide C_(5)H_(11)Br (A) reacts with ethanolic KOH to give an alkene 'B', which reacts with Br_(2) to give a compound 'C', which on dehydro-bromination gives an alkyne 'D'. On treatment with sodium metal inliquid ammonia one mole of 'D' gives one mole of the sodium salt of 'D' and half a mole of hydrogen gas. COmplete hydrogenation of 'D' yields a straight chain alkane. Identify A, B, C and D. Give the reactions involved.

Answer»

Solution :There actions involved in identification of A, B, C and D are as follows :
`C_(5)H_(11)Br(A) + alc. KOH rarr C_(5)H_(10)(B)`
`C_(5)H_(10)(B)+ Br_(2)//CS_(2) rarr C_(5)H_(10)Br_(2)(C)`
`C_(5)H_(10)Br_(2)(C) + alc. KOH rarr C_(5)H_(8)(D)` Alkyne.
`2C_(5)H_(8) + 2Na rarr 2C_(5)H_(7)Na + H_(2)`
HYDROGENATION of alkyne (D) gives straight chain alkane hence all the compounds A, B, C and D must be straight chain compounds. Alkyne gives sodium alkenyde which proves D is terminalalkyne.
33.

An alkyl halide by formation of its Grignard reagent and heating with water gives propane. What is the original alkyl halide ?

Answer»

methyl iodide
ethyl iodide
ethyl bromide
propyl bromide

Solution :`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)`
34.

An alkyl bromide (X) reacts with sodium in ether to form 4,5-diethyloctane, the compound 'X' is

Answer»

`CH_3(CH_2)_3 Br`
`CH_3(CH_2)Br`
`CH_3(CH_2)_3CH(Br)CH_3`
`CH_3-(CH_2)_2-CH(Br)-CH_2CH_3`

Solution :`2CH_3-(CH_2)_2-oversetoverset(""CH_2CH_3)|CH-Br+2Na UNDERSET"(WURTZ reaction)"OVERSET"Dry ether"tounderset"4,5-Diethyloctane"(overset1CH_3-overset"2-3"((CH_2))_2-oversetoverset(""CH_3CH_2)|underset4" CH"-oversetoverset("" CH_2CH_3)|underset5" CH"-overset"6-7"(("" CH_2)_2)-overset8CH_3-2NaBr)`
Thus , option (d) is CORRECT.
35.

An alkyl bromide produces a single alkene when it reacts with sodium ethoxide and ethanol. This alkene undergoes hydrogenation and products 2-methylbutane. What is the identify of the alkybromide ?

Answer»

1-bromo-2-methylbutane
1-bromobutane
1-bromo-2,2-dimethylpropane
2-bromo-2-methylbutane

Answer :A
36.

An alkene with molecular formula C_7H_14 gives propanone and butanal on ozonolysis. Write down its structural formula.

Answer»


ANSWER :`CH_(3)CH_(2)CH_(2)CH = C(CH_(3))_(2)`, 2-methylhex-2-ene
37.

An alkene (W) having molecular formula C_6H_(12) gives a hydrocarbon (X) C_6H_(14) on catalytichydrogenation and compound (X) gives two monochloro structural isomeric product (Y) and (Z). The structure of alkene (W) is :

Answer»

`CH_3 - CH_2 - CH_2 -CH_2 - CH_2 -CH=CH_2`

`CH_3-underset(CH_3)underset(|)C=CH-CH_2-CH_3`

SOLUTION :Compound X MUST contain only TWO different TYPES of hydrogen atoms.
38.

An alkene on reductive ozonolysis gives two molecules of CH_2(CHO)_2 . The alkene is

Answer»

2,4-hexadiene
1,3-cyclohexadiene
1,4-cyclohexadiene
1-methyl-1,3-cyclopentadiene

Solution :
39.

An alkene on ozonolysis yields only ethanal. There is an isomar of this, which on ozonolysis yields:

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PROPANONE and methanal
Propanone and ethanal
Ethanal and methanal
Only propanone

Solution :`"ALKENE" UNDERSET((2) Zn-H_(2)O)overset((1) O_(3))rarr CH_(3)CHO` only
40.

An alkene on ozonolysis gives a mixture of ethanal and pentan-3-one. Write the structure and IUPAC name of the alkene.

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SOLUTION :The PRODUCTS of OZONOLYSIS are :
41.

An alkene is most likely to reach with

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A FREE radical
An alkali
A nucleophile
An electrophile

Answer :D
42.

An alkene gives propan-2-one and 2-methylpropanal on ozonolysis. Identify the alkene. What products will be obtained when it is treated with hot and concentrated KMnO_4 ?

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SOLUTION :The PRODUCTS of OZONOLYSIS are
43.

An alkene (A) overset("Ozonolysis")to (##RES_CHM_SIPOC_E02_002_Q01.png" width="80%"> , A is

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ANSWER :C
44.

An alkene "A" on reaction with O_3 and Zn gives propanone and acetaldehyde in equimolar Addition of HCl to alkene "A" gives "B" as the product. The structure of product "B" is:

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ANSWER :A
45.

An alkene 'A' on ozonolysis gives a mixture of ethanal and pentan-3-one . Write the structures and IUPAC name of 'A'.

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Solution :WRITE the structures of the products of ozonolysis side by side with their oxygen ATOMS pointing TOWARDS each other. Remove the oxygen atoms and join the two ends by a double BOND, the STRUCTURE of the alkene 'A' is
46.

An alkene 'A' on ozonolysis gives a mixture of ethanal and pentan-3-one. Write structure and IUPAC name of 'A'.

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Solution :
: SELECTION of structure of alkene from the ozonolysis :
write the structure of ozonolysis of product.
Remove oxygen from the structure
Carbon CONTAINING oxygen put the double bond.
Put the SUBSTITUTION of the both carbon.
47.

An alkene ‘A’ on ozonolysis gives a mixture of ethanal and pentan-3-one. Write structure and IUPAC name of ‘A’.

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SOLUTION :The PRODUCTS of OZONOLYSIS are

The IUPAC name of the COMPOUND is 3-ethylpent-2-ene.
48.

An alkene 'A' contains three C-C, eight C-H, sigma-bonds , and one C-C pi-bond . 'A' on ozonolysis gives two moles of an aldehyde of molar mass 44 u write the IUPAC name of 'A'

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Solution :(i)An aldehyde with MOLAR mass 44 uis ethanal, `CH_3CH=O`
(ii)Write two moles of ethanal SIDE by side with their oxygen ATOMS pointing towards each other. Remove the oxygen atoms and join them by a double bond, the STRUCTURE of alkene 'A' is

As required , but-2-ene has three C-C, eight C-H `sigma`-bonds and one C-C `pi`-bond.
49.

An alkene ‘A’ contains three C – C, eight C – H (sigma)bonds and one C – C (pi) bond. ‘A’ on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write IUPAC name of ‘A’.

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Solution : The aldehyde having MOLAR mass 44 U is ethanal, `CH_3CHO` . Since, the ALKENE A on ozonolysis gives two moles of ethanal, `(CH_3 - undersetoverset(|)(H)(C) = O)`, its structure can be obtained by removing O ATOMS from two molecules of ethanal and joining them together by a double bond. THUS, the alkene A has the following structure :
As shown above, but-2-ene has three C-C, eight C-H o-bonds and one C-C `pi`- bond.
50.

An alkene 'A' contains three C-C, eight C-H sigma bonds and one C-C pi-bond. 'A' on ozonolysis gives two moles of an aldehyde of molar mass 44u. Write IUPAC name of 'A'.

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Solution :Product is formed of molecular weight 44u ALDEHYDE.
Aldehyde GROUP is CHO = 12 + 1 + 16 = 29
TOTAL weight `= 44-29 = 15 -= CH_(3)` group
`therefore` Product 1 is aldehyde `CH_(3)CHO`.
From 2 moler of `CH_(3)CHO`, product alkene is formed.

`underset("But-2-ene")(CH_(3)CH=CHCH_(3))`(A)
Structure of but-2-ene with bonds are as follows :
`Hoverset(sigma)(-)underset(H)underset(|sigma)overset(H)overset(|sigma)(C)overset(sigma)(-)overset(H)overset(|sigma)(C)underset(sigma)overset(sigma)(=)overset(H)overset(|sigma)(C)overset(sigma)(-)underset(H)underset(|sigma)overset(H)overset(|sigma)(C)overset(sigma)(-)H`
In these structure these are C-C `sigma` bond.
+ These structure has 8 C-H `sigma`-bond.
+ These structure has 1 C-C `pi`-bond.
All DETAILS relates with the que asked.
`therefore` Main product is But-2-ene.