(www.entrance-exam.net)-cbse class 12 sample paper 1

8/3/2019 (Www.entrance-exam.net)-CBSE Class 12 Sample Paper 1

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I Series: SSOII C od e. N o . 56/1/ O f.Roll No.i P r . . . r . I 1 J I l u 1 1 1 Please check that this question paper contains 12 printed pages. Code number given on the right hand side of the question paper should be written ontitle page of the answer-book by the candidate .. Please check that this question paper contains 30 questions. Please write down the serial number of the question before attempting it. 15 Minutes time has been allotted to read this question paper. The question paper wiIldistributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the student will read the questpaper only and will not write any answer on the answer script during this period. ~~ w~ fcv~ mq 'q'5 fit~~ 12 t I mq~'q'5fit~ ~ c it ~ f u r T I l t m'~ 'fit tffif dfI't-~ ifl ~-~ 1 : R . f t ; r @ I


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1. Which point defect in crystals does not alter the density of the relevant solid?r~f2MlC fiT ~ m ~ (~) ~ ~ am i f; - ~ i f q R c l i 4 ~ ~ Cfi{ffi ?

2. Define the term 'Tyndall effect' ,

3. Why is the froth flotation method selected for the concentration of Sulphide ores?

4. Why is Bi(v) a stronger oxidant than Sb(v) ?

5. Give the IUPAC name of the following compound:CH3 - C = C - CH20H! ICH3 Br

f . : rJ 4 ~ C fiT ~ ~ 1 f t 1Zm (IUPA C) ~ ~ :CH3-f = f -CH20H

CH3 Br

6. Write the structure of 3~oxopentanal.

. 7. Why is an alkylamine more basic than ammonia?


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A reaction is of second order with respect to a - reactant. How will the rate of reacbe affected if the concentration of this reactant is(i) doubled,(ii) reduced to half?~~*,~~~~~mqfft: 11fRW~~~(i) ~ c nr~ ~ , ~ .(ii) J IT I : I T ~ W I T ~ ,

ill ~ < i t G : \ ~ w : n f c m i t r fT ?. Explain the role of

(i) Cryolite in the electrolytic reduction of alumina.(ii) Carbon monoxide in the purification of nickel.f . :p := ,? f iT ~ ~ :(i) l{q.i"HI * ' ~ ~ ~ fl l q lZ '1 (~ C : ~ C f i " T 4 I _(ii) ~ ~ * ' qfh;:p{ 0 I ~ ~ l 1 T : : I T , 3 : i i C R " l1 $ '5 ~ C f i " l 1 t I

. Draw the structures of the following molecules:(i) XeF4(ii) BrF3f . : p : = , a r u r z : r r c n 1 { iI'iIQ ~ ~ :(i) XeF4(ii) BrF3

. Complete the following chemical reaction equations:(i) p4(5) + NaOH(aq) + ~O(l) ------?(ii) I-(aq) + ~O(l) + 03(g)------?f . : p : = , { IB lq F "" I C f i ~ tp: i" j i:Hori q : : ; " f - ~ ~ :(i) p4(5) +NaOH(aq) + ~O(J)------?(ii) I-(aq) + H 20(I) + 03(g)------?


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14. Which ones in the following pairs of substances undergoes SN2 substitution reactiofaster and why?(i)


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. Draw the structures of the monomers of the following polymers:(i) Teflon(ii) Polythene

ORWhat is the, repeating unit in .the condensation polymer obtained by combiningH02CCH2C~C02H (succinic acid) and ~NC~C~~ (ethylene diamine).f .: r; :: r ~ ifi~i;flt:1 f l l c f i r ( O J < i I ' 1 I Q ~ ~ :(i) ~(ii) q l ~ " l i q l ' " l

aremH02CC~C~C02H ( f 1 C R f i f - " l C f 1 ~ ) a i R ~NC~CH2NHz ~ g l ~ Q J O t l ' " l ) ifi~itmGI ~ ~ it ~ 3tR C I T f f iFfm ~ ?

. Iron has a body centred cubic unit cell with a cell edge of 286.65 pm. The density oiron is 7.87 g crrr". Use this information to calculate Avogadro's number (At. masofFe ::; 56 g mol ").3WR'1 Cfif ~ C fi l 'G f ~ E l ' " l l < : f i < t f c f iC f i ' ~ wm ~ I ~ t f c f iC f i ' ~ ifi " C t J l \ c t f r ~286.65 pm m f f i ~ I ~ Cfif ~ 7.87 g cm-3 ~ I W f I " ~ Cfif ~ r m : - f f ~ Qqlql!t t & u < ; f i T qRi;fl(>H~ I (Fe Cfif~ SiCl l4H = 56 g mol ")

. 100 mg of a protein is dissolved in just enough water to make 10.0 mL of solution, Ithis solution has an osmotic pressure of 13.3 mm Hg at 25C, what is the molar mas~~~~?(R= 0.0821 L atm mol-l K-1 and 760 mm Hg::;1 atm.)~ miR c t f r 100 mg l1BIT c it ~ ~ l:fBrT it ~ ~ 10.0 m L ~ "RJ lIT'TT< rr ~< m : W f I " ~ Cfif 25C e r r q m n o n ~ 13.3 mm Hg itm miR Cfif " 4 l f f i 044 H Cfm~' ?(R:::; 0.0821 L atm mol> K-I~~ cll''114og{'1~ = 760 mm Hg )

. A first order reaction has a rate constant of 0.0051 min-I. If we begin with 0.10 M


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How are the following colloids different from each other in respect of dispersmedium and dispersed phase ? Give one example of each type.(i) An aerosol (ii) A hydrosol (iii) An emulsionl1 f t~~~~qf t~~mi fRP lCf l l~ !~ ;g fml~~~ i t f t ~?w i t cn~ 'C f l T ~ - ~ d( Ie>{OI m ~ :(i) Igl*lIM (ii) e>1~11*lIM (iii) ~

Account for the following :(i) N H3 is a stronger base than P H3.(ii) Sulphur has a greater tendency for catenation than oxygen.(iii) Bond dissociation energy of F2 is less than that 'of Clz'

ORExplain the following situations:(i) In the structure of RN03 molecule, the N - 0 bond. (121pm) is shorterN - OR bond (140 pm),(ii) SF4 is easily hydrolysed whereas SF6 is not easily hydrolysed.(iii) XeF2 has a straight linear structure and not a bent angular structure.f . :r r; :r ~ a w:TTr ~ C f iR 'U T ~ :(i) PH3 qft ,3WlIDNH3 - 3 M ' > f 6 r M ' , & T I t t I(ii) 3 l 1 C f ' { f l ' i 1 ' 1 q ft ~~if ~~ aMitffit I(iii) P 2 c i t ~ f C l 4 1 ' l " 1 ' " " 1Rlz qft~ f C l 4 1 ' l " 1 ' " " 1H# O f i 1 1 i t f I T t IRP l 'q\ lCW IT3IT~ *ll1$1l $ i l :(i) HN 0 O J c t f t ~ if, N - 0 ~ (121 pm) N - O H ~ (140 pm) q ft 3I1tlID


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4. For the complex [Fe(en)zClz]Cl, (en = = ethylene diamine), identify(i) the oxidation number of iron,(ii) the hybrid orbitals and the shape of the complex,(iii) the magnetic behaviour of the complex,(iv) the number of geometrical isomers,(v) whether there is an optical isomer also, and(vi) name of the complex. (At. no. of Fe = = 26)

5.. Explain the mechanism of the following reactions:(i) Addition of Grignard's reagent to the carbonyl group of a compound form

an adduct followed by hydrolysis.(ii) Acid catalysed dehydration of an alcohol forming an alkene.(iii) Acid catalysed hydration of an alkene forming an alcohoLf . ; r : ; f ~ a : I T c n 1 f;t;ll \ f c i \ l : r e n 1 " & ! T f S Z I T ~ :


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26, Giving an example for each describe the following reactions:0) Hofmann's bromamide reaction(ii) Gatterman reaction(iii) A coupling reaction1A~ ~m~ 3~1i\{UI~ f . : r r = : r ~31T q;r qu f.:r ~ :(i) ~ e F r


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(b) Give an explanation for each of the following observations:(i) The gradual decrease in size (actinoid contraction) from element

element is greater among the actinoids than that among the lanthano(lanthanoid contraction).

(ii) The greatest number of oxidation states are exhibited by the memberthe middle of a transition series.

(iii) With the same d-orbital configuration (d4) c r 2 + ion is a reducing abut Mn3+ ion is an oxidising agent.

(i) Mn04{aq) + C20i-(aq) + H\aq) ~(ii) Cr20~-(aq) + Fe2+(aq) + H+(aq)~

(ii) qnJ~ " f f f < i f (-moo s t o r r ) < ) : ; ~ - q ~ m r y ; - m Q - 3 1 1 ' 4 " ' < = i tT$fl ~ ~;-(iii) Q f C k ' " " l I . 4 ' S s t o r r c f i "ff i 'C r~ ~ ~ifi ~


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(a) f.;p::,~Wff~~~:(i) ~~~~;:;JjhCfl~,(ii) 210':l~1~ ~;:;JjIP;gt}'I~'5I

oII(ii) 0+ ,..........Anhydrous AlCl3 ) O C . . . . .H 3

oII(iii) 0+ :.. O C D

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(www.entrance-exam.net)-cbse class 12 sample paper 1

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