cbse board paper 2014 set 1

8/10/2019 Cbse Board Paper 2014 Set 1

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Cbse board paper 2014 set 1 delhi

General Instructions:(i) All questions are compulsory(ii) Question numbers 1 to 8 are very short-answer questions and carry 1 mark each.(iii) Question numbers 9 to 18 are short-answer questions and carry marks each.(iv) Question numbers 19 to ! are also short-answer questions and carry " marks.(v) Question numbers 8 to "# are lon$-answer questions and carry % marks each.(vi) &se 'o$ ables i* necessary. &se o* calculators is not allowed.

Question 1

Questions

Q1+ive one e,ample each o* oil in water and water in oil emulsion. Solution:

Type of emulsion Example

Oil in water Milk, vanishing cream (any one)

Water in oil Butter, cold cream (any one)

Q2

hich reducin$ a$ent is employed to $et copper *rom the leached low-$rade copperore/Solution:

Copper can be obtained from lowgrade ore through the process of leaching using acid or

bacteria (leaching is a process in which ore is treated with suitable reagent that dissolves ore but

not the impurities)!

"he solution containing copper can be reduced with the help of reducing agents such as scrap

iron or #$to get copper metal!

Cu$%(a&) % 'e Cu(s) % 'e$%(a&) Cu$% (a&) % #$(g) Cu(s) % $ #

%(a&)

Q3hich o* the *ollowin$ is a more stable comple, and why /

[Co(NH3)6]3+and [Co(en)3]3+Solution:
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Chelating ligands form more stable complees compared to nonchelating ligands! *ince

ethylene diammine is a bidentate ligand and forms stable chelate, +Co(en) -%will be a more

stable comple than +Co(.#)/-%.

Q4rite the 0&A2 name o* the compound.

Solution:

"he 0123C name of the given organic compound is #ydroybutan4oic acid. Q5

hich o* the *ollowin$ isomers is more volatile3o-nitrophenol or p-nitrophenol/Solution:

o-nitrophenol *orms intra-molecular hydro$en bond. 4n the other hand p-nitrophenol isinvolved in stron$er inter-molecular hydro$en bondin$ and hence it has hi$her boilin$point than o-nitrophenol. 5o o-nitrophenol is more volatile than p-nitrophenol.

Q6hat are isotonic solutions/

Solution:

0sotonic solutions are those solutions that have the same osmotic pressure at a $iventemperature.

Q7Arran$e the *ollowin$ compounds in increasin$ order o* solubility in water 3267%7 (27%)7 27%7Solution:

he increasin$ order o* solubility in water o* the $iven compounds is as *ollows3267%7 (27%)7 27%7he more e,tensive the 7:bondin$ the hi$her is the solubility o* the compound in

water. 27%7contains two 7-atoms whereas (27%)7 contains only one 7-atom.here*ore 27%7is more soluble than (27%)7. he solubility o* 267%7 is leastdue to its hi$h molecular mass.

Q8hich o* the two components o* starch is water soluble/Solution:
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5tarch contains two components3 Amylose and Amylopectin.Amylose is the water-soluble component.

QAn element with density 11. $ cm;"*orms a *.c.c. lattice with ed$e len$th o* < = 1#;8cm.2alculate the atomic mass o* the element.

(+iven 3 A> 6.# = 1#"mol;1)Solution:

5iven,

6ensity, d 7 44!$ g cm

8dge length,a7 9 : 4;


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2alculate the mass o* a compound (molar mass > %6 $ mol :1) to be dissolved in !% $o* ben@ene to lower its *ree@in$ point by #. %.1 k$ mol

:1).Solution:

Gien!T"=0.4# $$"=%.12 $ &g 'o1w1= 7% gw2=M2=2%6 g 'o1*ingT"=$"w21000M2w1w2=,T"M2w1$"1000=0.4#2%67%%.121000=1.# g

Q12Be*ine an ideal solution and write one o* its characteristics.Solution:

Definition:

"he solutions that obey ?aoult@s law over the entire range of concentration are called ideal

solutions! 8amplesA nheane and nheptane

Characteristics:

'or ideal solutionsA

o 8nthalpy of miing (miH)of the pure components to form the solution is ero!

o Dolume of miing (miV)is also e&ual to ero!

Q13rite two di**erences between order o* reaction and molecularity o* reaction.Solution:

Order Molecularity

"he overall order of reaction is the sum of

all the eponents of all the reactants presentin the rate law epression!

0t is the number of reacting species taking

part in an elementary reaction, which must

collide simultaneously in order to bringabout a chemical reaction!

0t is determined eperimentally! 0t is a theoretical concept!

0t may be e&ual to ero or have fractionalvalues!

0t can not be e&ual to ero and it alwayshave integral values( which cannot eceeds)

Q144utline the principles behind the re*inin$ o* metals by the *ollowin$ methods3(i) Cone re*inin$ method(ii) 2hromato$raphic methodSolution:

(i) !one re"inin# $ethod:Cone re*inin$ method is based on the principle that impurities are more soluble in the

molten state than in the solid state o* a metal.his method is used in the puri*ication o* elements like +ermanium(+e) 5ilicon(5i)0ndium (0n) etc.

(ii)Chro%ato#raph& %ethod:2hromato$raphy is the technique used *or separation o* the components o* a mi,turethat are soluble in the same solvent and are di**erently adsorbed on an adsorbent. histechnique was *irst used *or separation o* colours and hence the name. here are two
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phases in chromato$raphy - the stationary phase and the mobile phase. hecomponents o* the mi,ture are absorbed di**erently in the stationary phase thus leadin$to their separation. here are many di**erent types o* chromato$raphy - paperchromato$raphy thin-layer chromato$raphy $as chromato$raphy etc.

Q15

2omplete the *ollowin$ chemical equations 3(i) 2a"D 74 E(ii) 2u D 754


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comple, in which the two chloride li$ands may be oriented cisandtransto each other.

Q17(i) hich alkyl halide *rom the *ollowin$ pair is chiral and under$oes *aster 5 reaction/

(ii) 4ut o* 51 and 5 which reaction occurs with

(a) 0nversion o* con*i$uration(b) KacemisationSolution:

(i)Amon$ the $iven pair o* compounds alkyl halide )b*has a chiral centre.

he alkyl halide )a*does not contain a chiral centre and and it also $ives *aster5reaction as 5 is more *avourable in primary alkyl halides.

(ii)(a) 0nversion o* con*i$uration takes place in 5 reaction.
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(b) Kacemisation takes place in 51 reaction.

Q18Braw the structure o* maLor monohalo product in each o* the *ollowin$ reactions 3

(i)

(ii)Solution:

(i)

(ii) Addition in presence o* pero,ide yields product accordin$ to anti-Jarkovnikov rule o*addition.

Q1(a) 0n re*erence to Freundlich adsorption isotherm write the e,pression *or adsorption o*$ases on solids in the *orm o* an equation.(b) rite an important characteristic o* lyophilic sols.(c) Gased on the type o* particles o* dispersed phase $ive one e,ample each o*associated colloid and multimolecular colloid.Solution:
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(a)

'reundlich adsorption isotherm for adsorption of gases on solidsAxm=Kp1n/ an ao e i//en aogxm=og K+ 1nog pwherexis the mass of the adsorbate, mis the mass of the absorbent andpis the pressure of thegas and n is a constant which is greater than 4!

(b)

Eyophilic sols are sols that are solventattracting! 3n important characteristic of these sols is thatif the dispersion medium is separated from the dispersion phase by any method, the sol can be

reconstituted by simply remiing the two again! "hat is why these sols are also known

as reversiblesols!

(c)?,ample o* associated colloid3 5oap solution?,ample o* multimolecular colloid3 +old sol

Q20(a) Braw the structures o* the *ollowin$ molecules3

(i) Me4F #.6#1 lo$ > #."#1#)Solution:

he thermal decomposition o* 542lat a constant volume is represented by the*ollowin$ equation3

A*ter time t total pressuret> #D p

which on rearran$ement $ives3

p> t: #

here*ore> #: tFor a *irst-order reaction

hen t> 1## s

k=2.303100og0.420.40.7= 1.3#71021

Q23(i) +ive two e,amples o* macromolecules that are chosen as dru$ tar$ets.(ii) hat are antiseptics / +ive an e,ample.(iii) hy is the use o* aspartame limited to cold *oods and so*t drinks /
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Solution:

(i)

8nyme and receptor are the macromolecules that are chosen as drug targets!

(ii)

%ntiseptics:"hese are applied to the living tissues such as wounds, cuts and diseased skinsurfaces!8amples of antiseptics are furacineandsoframicine!

(iii)3spartame is the most useful artificial sweetener! 0tFs use is limited to cold foods and soft drinks

because it is unstable at cooking temperature!

Q24(i) Be*iciency o* which vitamin causes ni$ht-blindness/(ii) ame the base that is *ound in nucleotide o* KA only.(iii) +lucose on reaction with 70 $ives n-he,ane. hat does it su$$est about thestructure o* $lucose/Solution:

i) i$ht blindness is caused due to the de*iciency o* vitamin A.

ii) &racil is the base that is *ound only in the nucleotide o* KA.

iii) he reaction o* $lucose with 70 $ivin$ n-he,ane su$$ests that all the si, carbonatoms are linked in a strai$ht chain as shown in the reaction $iven below3

274-(2747)


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'or eample, polyGhydroybutyrateCOG hydroy valerate (2#BD) is a biodegradable

aliphatic polyester!

(iii) 2olythene is an addition polymer that is formed by addition of ethene molecules!

Q26(a) rite the mechanism o* the *ollowin$ reaction 3CH3CH2H- H CH3CH2+H2

(b) rite the equation involved in Keimer-iemann reaction. Solution:

a&"he reaction proceeds through nucleophilic substitution bimolecular (*.$) mechanism, as shownA

0nversion of configuration takes place during the reaction!

b!

!eimer'Tiemann reaction:

Q27+ive the structures o* A G and 2 in the *ollowin$ reactions 3

(i)


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(ii)

'(

7ow will you convert the *ollowin$/(i) itroben@ene into aniline

(ii) ?thanoic acid into methanamine

(iii) Aniline into :phenylethanamide

(rite the chemical equations involved.)Solution:

(i)

(ii)

'((i) itroben@ene into aniline

(ii) ?thanoic acid into methanamine


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(iii) Aniline into :phenylethanamide

Q28(a) Be*ine the *ollowin$ terms 3

(i) 'imitin$ molar conductivity

(ii) Fuel cell

(b) Kesistance o* a conductivity cell *illed with #.1 mol ' :12l solution is 1## O. 0* theresistance o* the same cell when *illed with #.# mol ' :12l solution is %# O calculatethe conductivity and molar conductivity o* #.# mol ':12l solution. he conductivity o*#.1 mol ':12l solution is 1.9 = 1#:O:1cm:1.

'(

(a) 5tate Faradays *irst law o* electrolysis. 7ow much char$e in terms o* Faraday isrequired *or the reduction o* 1 mol o* 2uDto 2u.

(b) 2alculate em* o* the *ollowin$ cell at 98 3J$(s) P J$D(#.1 J) PP 2uD(#.#1) P 2u(s)H+iven ?ocell > D.!1 1 F > 96%## 2 mol

;1ISolution:

(a)(i) hen concentration o* an electrolyte approaches @ero then its molar conductivity isknown as limitin$ molar conductivity.(ii)Fuel cells are the $alvanic cells in which the ener$y o* combustion o* the *uels likehydro$en methanol. etc is directly converted into electrical ener$y.

(b)+iven that32oncentration o* the 2l solution > #.1 mol ':1

Kesistance o* cell *illed with #.1 mol ':12l solution > 1## ohm2ell constant > +R> conductivity resistance1.9=1#: ohm:1cm:1= 1## ohm > 1.9 cm:1> 19 m:1

2ell constant *or a particular conductivity cell is a consant.


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2onductivity o* #.# mol ':12l solution> Ce on/an/8ei/ane>G8=129 '1%20 o:'=0.24# ;'12oncentration > #.# mol ':1

> 1####.# mol m:"> # mol m:"

ow

Jolar conductivity >Eocell= +2.71 VT= 29# KAoding /o /:e Nen/ e?a/ion!E= Eocell0.0%912og[@g2+][C2+]= 2.71 0.0%912og0.10.01=2.710.029% og 10 = 2.71 0.029%=2.6#0% V

Q2(a) 7ow do you prepare3(i) Jn4


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(v) 2omplete the *ollowin$ equation3@n4+#H++%e-Solution:

a)i) Jn4


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5ince all the values are almost same there*ore all orbitals can involved in bondin$resultin$ in lar$er o,idation number *or actinoids.

4K

1)0n "d-series o* transition metals man$anese has an atomic number o* % that $ives theelectronic con*i$uration as HArI "d%


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(i) Gen@aldehyde and Gen@oic acid (ii) ropanal and ropanone

'(

(a) Account *or the *ollowin$3 (i) 27"274 is more reactive than 27"2427"towards reaction with 72. (ii) 2arbo,ylic acid is a stron$er acid than phenol.(b) rite the chemical equations to illustrate the *ollowin$ name reactions3 (i) ol**-ishner reduction (ii) Aldol condensation (iii) 2anni@@aro reactionSolution:

(a)(i)

(ii)

(iii)

(b)(i) Benaldehyde and Benoic acid

Test'$ Throu(h sodium bicarbonate

Benaldehyde does not react with sodium bicarbonate! #owever, benoic acid will produce briskeffervescence on reaction with sodium bicarbonate as shown in the given reactionA

C/#HCOO# % .a#CO-C/#HCOO.a % #$O % CO$

Test') Throu(h Tollen*s rea(ent

Benaldehyde reacts with ammoniacal solution of silver nitrate to form a silver mirror!

C6#HC#O % $+3g(.#)$-%% O#I-C/#HCOOI% $3g % $#$O % 9.#

#owever, no such reaction is given by benoic acid!(ii)

Test'$ +odoform Test

2ropanone gives positive iodoform test, as it contains C#CO group, whereas propanal does notgive iodoform test! "he reaction is as followsA


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CH3CH2CH + 32+ 4NaH - No ea/ionHea/Boana

O!

(a)(i)

C#COC#is stericallyhindered than C#C#Odue to the presence of alkyl group on both sides

of the carbonyl carbon, making them less reactive towards nucleophilicattack because bothmethyl groups have electron releasing tendency due to 0 effect! "hese alkyl groups

make ketoneless reactive by donating electron to carbonyl group!"herefore, acetaldehyde is

more reactive towards reaction with #C.!

(ii)

Carboylic acids are acidic due to resonance stabilisation of carboylateanion and in phenols,

acidic character is present due to resonance stabilisation ofphenoideanion! Carboylic acidsare more acidic than phenols because the negative charge in carboylateanion is more spread out

compared to thephenoideion, as there are two electronegative Oatoms in carboylateanion

compared to one inphenoideion! 0n the resonance structures of carboylateanion, the negativecharge is present on the Oatoms, while in resonance ofphenoideion, negative charge is also

present on electropositive carbon atom, which leads to less stability ofphenoideion

than carboylateanion!

(b)


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cbse board paper 2014 set 1

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