56/2/1 1 P.T.O.

narjmWu H$moS >H$mo Cma-nwpVH$m Ho$ _wI-n >na Ad` {bIo & Candidates must write the Code on the

title page of the answer-book.

Series OSR/2 H$moS> Z. 56/2/1 Code No.

amob Z. Roll No.

agm`Z {dkmZ (gmpVH$) CHEMISTRY (Theory)

{ZYm[aV g_` : 3 KQ>o A{YH$V_ AH$ : 70

Time allowed : 3 hours Maximum Marks : 70

H$n`m OmM H$a b| {H$ Bg Z-n _o _w{V n> 15 h &

Z-n _| Xm{hZo hmW H$s Amoa {XE JE H$moS >Z~a H$mo N>m Cma-nwpVH$m Ho$ _wI-n> na {bI| &

H$n`m OmM H$a b| {H$ Bg Z-n _| >30 Z h &

H$n`m Z H$m Cma {bIZm ew$ H$aZo go nhbo, Z H$m H$_mH$ Ad` {bI| & Bg Z-n H$mo nT>Zo Ho$ {bE 15 {_ZQ >H$m g_` {X`m J`m h & Z-n H$m {dVaU nydm

_| 10.15 ~Oo {H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>m Ho$db Z-n H$mo nT>|Jo Ama Bg Ad{Y Ho$ XmamZ do Cma-nwpVH$m na H$moB Cma Zht {bI|Jo &

Please check that this question paper contains 15 printed pages.

Code number given on the right hand side of the question paper should be

written on the title 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 will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the

students will read the question paper only and will not write any answer on

the answer-book during this period.

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gm_m` {ZX}e :

(i) g^r Z A{Zdm` h &

(ii) Z-g`m 1 go 8 VH$ A{V bKw-Cmar` Z h & `oH$ Z Ho$ {bE 1 AH$ h &

(iii) Z-g`m 9 go 18 VH$ bKw-Cmar` Z h & `oH$ Z Ho$ {bE 2 AH$ h &

(iv) Z-g`m 19 go 27 VH$ ^r bKw-Cmar` Z h & `oH$ Z Ho$ {bE 3 AH$ h &

(v) Z-g`m 28 go 30 VH$ XrK-Cmar` Z h & `oH$ Z Ho$ {bE 5 AH$ h &

(vi) Amd`H$VmZwgma bmJ Q>o~bm| H$m `moJ H$a| & H$Hw$boQ>am| Ho$ Cn`moJ H$s AZw_{V Zht h &

General Instructions :

(i) All questions are compulsory.

(ii) Questions number 1 to 8 are very short-answer questions and carry 1 mark each.

(iii) Questions number 9 to 18 are short-answer questions and carry 2 marks each.

(iv) Questions number 19 to 27 are also short-answer questions and carry 3 marks each.

(v) Questions number 28 to 30 are long-answer questions and carry 5 marks each.

(vi) Use Log Tables, if necessary. Use of calculators is not allowed.

1. \o$Z bdZ {d{Y _| A`H$m| H$mo gm{V H$aZo _| gJmhH$m| (collectors) H$m `m H$m ` hmoVm

h ? 1

What is the function of collectors in the froth floatation process for the

concentration of ores ?

2. ^m{VH$ A{YemofU hmoZo _| {H$g H$ma Ho$ ~b CmaXm`r hmoVo h ? 1

What type of forces are responsible for the occurrence of physisorption ?

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3. EH$b N N Am~Y EH$b P P Am~Y go X~b `m| hmoVm h ? 1

Why is the single N N bond weaker than the single P P bond ?

4. {ZZ{b{IV gH$a {H$g H$ma H$s g_md`dVm (isomerism) X{eV H$aVm h : 1

[Co(NH3)6][Cr(CN)6]

What type of isomerism is shown by the following complex :

[Co(NH3)6][Cr(CN)6]

5. b.c.c. EoH$H$ gob _| na_mUw {`m (r) Ama gob Ho$ {H$Zmao H$s b~mB (a) Ho$ Amngr

g~Y H$mo `$ H$s{OE & 1

Express the relationship between atomic radius (r) and the edge

length (a) in the b.c.c. unit cell.

6. {ZZ{b{IV `m{JH$ H$m AmB.`y.nr.E.gr. (IUPAC) Zm_ {b{IE : 1

Write the IUPAC name of the following compound :

7. BZ XmoZm| _| go H$mZ-gm A{YH$ jmar` h Ama `m| ? 1

Which of the two is more basic and why ?

8. Q>mM ~ZmZo dmbo -byH$moO Ho$ Xmo KQ>H$m| Ho$ Zm_ {b{IE & 1

Name the two components of -glucose which constitute starch.

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9. Ni(NO3)2 Ho$ EH$ {db`Z H$m b{Q>Z_ Ho$ BboQ>moS>m| Ho$ ~rM 5.0 Eonr`a {dwV Ymam go

20 {_ZQ> VH$ dwV AnKQ>Z {H$`m J`m & H$WmoS> na {ZH$b H$m {H$VZm `_mZ {Zjo{nV

hmoJm ? 2

({X`m J`m h : {ZH$b H$m na_mUw `_mZ = 58.7 g mol1, 1 F = 96500 C mol1)

A solution of Ni(NO3)2 is electrolysed between platinum electrodes using

a current of 5.0 ampere for 20 minutes. What mass of nickel will be

deposited at the cathode ?

(Given : At. Mass of Ni = 58.7 g mol1, 1 F = 96500 C mol1)

10. A{^{H$`m H$s AY Am`w H$s n[a^mfm {b{IE & {ZZ Ho$ AY Am`w Ho$ {b o` `OH$ {b{IE : 2

(i) ey` H$mo{Q> H$s A{^{H$`m

(ii) W_ H$mo{Q> H$s A{^{H$`m

Define half-life of a reaction. Write the expression of half-life for

(i) zero order reaction and

(ii) first order reaction.

11. {gda A`H$ go {gda Ho$ {ZH$fU go g~ amgm`{ZH$ A{^{H$`mE {b{IE & 2

Write the chemical reactions involved in the extraction of silver from

silver ore.

12. g\$a Ho$ Xmo A{V _hdnyU Ana$nm| Ho$ Zm_ {b{IE & BZ XmoZm| _| go H$mZ-gm H$j Vmn

na Wm`r hmoVm h ? `m hmoVm h O~ Wm`r $n H$mo 370 K go D$na Ja_ {H$`m OmVm h ? 2

AWdm

(i) gnH$ {d{Y go H2SO4 H$s m{ H$mo A{YH$V_ ~ZmZo Ho$ {V~Y {b{IE &

(ii) Ob _o H2SO4 Ho$ {bE Ka2

56/2/1 5 P.T.O.

Name the two most important allotropes of sulphur. Which one of the two

is stable at room temperature ? What happens when the stable form is

heated above 370 K ?

OR

(i) Write the conditions to maximize the yield of H2SO4 by contact

process.

(ii) Why is Ka2 H$s Obr` KOH go A{^{H$`m H$s OmVr h &

(ii) O~ {ZOb AlCl3 H$s CnpW{V _| bmoamo~oOrZ H$s CH3COCl go A{^{H$`m H$s OmVr h &

Write chemical equations when

(i) ethyl chloride is treated with aqueous KOH.

(ii) chlorobenzene is treated with CH3COCl in presence of anhydrous

AlCl3.

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16. (a) {ZZ `w_m| go {H$g EopH$b hobmBS> H$s Amn SN2 {H$`m{d{Y mam A{YH$ VrdVm go A{^{H$`m H$aZo H$s Amem H$a|Jo Ama `m| ? CH3 CH2 CH CH3 CH3 CH2 CH2 CH2 Br

Br

(b) SN1 A{^{H$`mAm| _| ao{g_rH$aU hmo OmVm h & `m| ? 2

(a) Which alkyl halide from the following pairs would you expect to

react more rapidly by an SN2 mechanism and why ?

CH3 CH2 CH CH3 CH3 CH2 CH2 CH2 Br

Br

(b) Racemisation occurs in SN1 reactions. Why ?

17. {ZZ A{^{H$`m H$s {H$`m{d{Y {b{IE : 2

OHBrCHCHHBr

OHCHCH 22323

Write the mechanism of the following reaction :

OHBrCHCHHBr

OHCHCH 22323

18. {ZZ A{^{H$`mAm| _| `w$ A{^H$maH$m| Ho$ Zm_ {b{IE : 2

(i) \$sZmb Ho$ ~mo_rZoeZ go 2,4,6-Q>mB~mo_mo\$sZmb ~ZmZm

(ii) `yQ>oZ-2-AmoZ go `yQ>oZ-2-Amob ~ZmZm

(iii) Eo{Zgmob H$m \$sS>ob H$mQ>g EopH$brH$aU

(iv) mW{_H$ EoH$mohmb Ho$ AmgrH$aU mam H$m~mopg{bH$ Ab ~ZmZm

Name the reagents used in the following reactions :

(i) Bromination of phenol to 2,4,6-tribromophenol

(ii) Butan-2-one to Butan-2-ol

(iii) Friedel Crafts alkylation of anisole

(iv) Oxidation of primary alcohol to carboxylic acid

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56/2/1 7 P.T.O.

19. (i) KCl {H$g H$ma H$m agg_rH$aU{_Vr` Xmof {XImVm h Ama `m| ?

(ii) {g{bH$mZ H$mo As go S>mo{nV H$aZo na {H$g H$ma H$m AYMmbH$ ~ZVm h ?

(iii) {ZZ _| go H$mZ-gm AmpdH$ R>mog H$m CXmhaU h : CO2 AWdm SiO2

(iv) BZ_| go H$mZ-gm A{YH$ AN>o Mw~H$ ~ZmEJm, \o$amoMw~H$s` nXmW AWdm \o$arMw~H$s` nXmW ? 3

(i) What type of stoichiometric defect is shown by KCl and why ?

(ii) What type of semiconductor is formed when silicon is doped with

As ?

(iii) Which one of the following is an example of molecular solid :

CO2 or SiO2

(iv) What type of substances would make better magnets,

ferromagnetic or ferrimagnetic ?

20. (i) gmYmaU gob H$s VwbZm _| H2 O2 BYZ gob Ho$ Xmo bm^ {b{IE &

(ii) ZrMo Xr JB gob A{^{H$`m Ho$ {b o` gm` pWamH$ (Kc) 10 h & BgHo$ {b o` o

Egob

n[aH${bV H$s{OE &

3

(i) Write two advantages of H2 O2 fuel cell over ordinary cell.

(ii) Equilibrium constant (Kc) for the given cell reaction is 10.

CalculateocellE .

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21. pWa Am`VZ AdWm _| SO2Cl2 Ho$ W_ H$mo{Q> Ho$ D$_r` AnKQ>Z _| {ZZ AmH$S>oo m

hE Wo :

)g(Cl)g(SO)g(ClSO 2222

`moJ g_`/s1 gH$b Xm~/atm

1 0 0.4

2 100 0.7

doJ pWamH$ n[aH${bV H$s{OE & ({X`m J`m h : log 4 = 0.6021, log 2 = 0.3010) 3

The following data were obtained during the first order thermal

decomposition of SO2Cl2 at a constant volume :

)g(Cl)g(SO)g(ClSO 2222

Experiment Time/s1 Total pressure/atm

1 0 0.4

2 100 0.7

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

22. (a) R>mogm| na Jgm| Ho$ A{YemofU Ho$ {bE \$m` S>{bH$ A{YemofU g_Vmnr (isotherm) Ho$ {bE EH$ g_rH$aU Ho$ $n _| `OH$ {b{IE &

(b) _IZ Ho$ n[a{j mdWm Ama n[ajon _m`_ `m h ?

(c) g_w Ama ZXr Ho$ {_bZo Ho$ WmZ na S>oQ>m ~ZVm h & `m| ? 3

(a) Write the expression for the Freundlich adsorption isotherm for

the adsorption of gases on solids, in the form of an equation.

(b) What are the dispersed phase and dispersion medium of butter ?

(c) A delta is formed at the meeting place of sea and river water.

Why ?

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56/2/1 9 P.T.O.

23. (a) bWoZm`S> H$mZ-H$mZ gr {d{^ CnMm`r AdWmE {XImVo h ?

(b) gH$_U Vdm| H$s Xmo {deofVmE {b{IE &

(c) 3d-bmH$ Ho$ Vdm| _| go {H$Z-{H$Z H$mo gH$_U Vd Zht _mZm Om gH$Vm h Ama `m| ? 3

AWdm

{ZZ Ho$ {bE Cn w`$ H$maU {b{IE :

(a) AnZr +3 AmgrH$aU AdWm H$mo m H$aZo Ho$ {bE Fe2+ `m{JH$mo H$s VwbZm _| Mn2+ `m{JH$ A{YH$ Wm`r hmoVo h &

(b) Sc (Z = 21) go Zn (Z = 30) VH$ Ho$ 3d grarO Ho$ Vdm| _| go Zn H$s na_mUwH$aU H$s EoWnr g~go H$_ hmoVr h &

(c) Obr` {db`Z _|o Sc3+ aJhrZ hmoVm h O~{H$ Ti3+ aJrZ hmoVm h & 3

(a) What are the different oxidation states exhibited by the

lanthanoids ?

(b) Write two characteristics of the transition elements.

(c) Which of the 3d-block elements may not be regarded as the

transition elements and why ?

OR

Assign suitable reasons for the following :

(a) The Mn2+ compounds are more stable than Fe2+ towards oxidation

to their +3 state.

(b) In the 3d series from Sc (Z = 21) to Zn (Z = 30), the enthalpy of

atomization of Zn is the lowest.

(c) Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.

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56/2/1 10

24. {ZZ A{^{H$`mAm| _| A, B Ama C H$s gaMZmE ~VmBE : 3

(i) K273

CHNO

BLiAlH

AKCN

BrCH 243

(ii)

CNaOHCHCl

BKOHBr

ANH

COOHCH 3233

Give the structures of A, B and C in the following reactions :

(i) K273

CHNO

BLiAlH

AKCN

BrCH 243

(ii)

CNaOHCHCl

BKOHBr

ANH

COOHCH 3233

25. {ZZ nXm| H$s n[a^mfmE {b{IE : 3 (a) EoZmo_a

(b) moQ>rZm| H$m {dH$VrH$aU

(c) Amd`H$ Eo_rZmoo Ab

Define the following terms :

(a) Anomers

(b) Denaturation of proteins

(c) Essential amino acids

26. (i) EoQ>r{hQ>m_rZ H$s EH$ CXmhaU g{hV n[a^mfm {b{IE &

(ii) {ZZ Amf{Y`m| _| go H$mZ-gr {VO{dH$ h :

_m\$sZ, Bdm{Zb, bmoaEo\${ZH$mob, Eopn[aZ &

(iii) EonmQ>o_ H$m Cn`moJ R>S>o ^moOZ Ama no` nXmWmo VH$ gr{_V `m| hmoVm h ? 3

(i) Define Antihistamine with an example.

(ii) Which one of the following drugs is an antibiotic :

Morphine, Equanil, Chloramphenicol, Aspirin.

(iii) Why is use of aspartame limited to cold food and drink ?

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56/2/1 11 P.T.O.

27. bmpQ>>H$ Ho$ Wbm| na {V~Y bJ OmZo Ho$ CnamV, EH$ Hy$b Ho$ N>mm| Zo {ZU` {b`m {H$

dh bmoJm| H$mo dmVmdaU Ama `_wZm ZXr na bmpQ>>H$ Ho$ Wbm| Ho$ hm{ZH$maH$ ^mdm| go

gy{MV H$a|Jo & ~mV H$mo A{YH$ ^mdr ~ZmZo Ho$ {bE, Chm|Zo Xgao Hy$bm| Ho$ gmW {_bH$a

EH$ abr aMr Ama gpO`m ~oMZo dmbm|, XH$mZXmam| Ama {S>nmQ>_oQ>b Q>moam| _| H$mJO Ho$

Wbo ~mQ>o & g^r N>mm| Zo U {H$`m {H$ do `_wZm ZXr H$mo ~MmZo Ho$ {bE ^{d` _| nmbrWrZ

Ho$ Wbm| H$m `moJ Zht H$a|Jo &

Cn w`$ boIme H$mo nT>H$a {ZZ Zm| Ho$ Cma Xr{OE : 3

(i) N>mm|o Zo {H$Z _y`m| H$mo Xem`m h ?

(ii) Od-{ZZrH$aUr` ~hbH$ `m hmoVo h ? EH$ CXmhaU Xr{OE &

(iii) `m nmbrWrZ EH$ g_ (hmo_mo) ~hbH$ h AWdm gh (co-) ~hbH$ h ?

After the ban on plastic bags, students of one school decided to create

awareness among the people about the harmful effects of plastic bags on

the environment and the Yamuna river. To make it more impactful, they

organized a rally by joining hands with other schools and distributed

paper bags to vegetable vendors, shopkeepers and departmental stores.

All students pledged not to use polythene bags in future to save the

Yamuna river.

After reading the above passage, answer the following questions :

(i) What values are shown by the students ?

(ii) What are biodegradable polymers ? Give one example.

(iii) Is polythene a homopolymer or copolymer ?

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28. (a) dmnerb Ad`dm| dmbo {db`Z Ho$ {bE amCQ> {Z`_ {b{IE & g^r gmUm|o Ama VmnH$_m| na amCQ> {Z`_ AZwgma ahZo dmbo {db`Z H$m Zm_ {b{IE & 2

(b) 200 g Ob _| 10 g CaCl2 KmobZo go m hE {db`Z Ho$ {bE dWZmH$ C`Z H$mo n[aH${bV H$s{OE & (Ob Ho$ {bE Kb = 0.512 K kg mol

1,

CaCl2 H$m _moba `_mZ = 111 g mol1) 3

AWdm

(a) {ZZ nXm| H$s n[a^mfmE {b{IE : 3

(i) pWadmWr (Eo{O`moQ>mon)

(ii) namgaUr (Amog_m{Q>H$) Xm~

(iii) AUwg` (H$mo{bJo{Q>d) JwUY_

(b) 9.8% (w/w) H2SO4 Ho$ {db`Z H$s _mobaVm n[aH${bV H$s{OE `{X Bg {db`Z

H$m KZd 1.02 g ml1 hmo & (H2SO4 H$m _moba `_mZ = 98 g mol1) 2

(a) State Raoults law for a solution containing volatile components.

Name the solution which follows Raoults law at all concentrations

and temperatures.

(b) Calculate the boiling point elevation for a solution prepared by

adding 10 g of CaCl2 to 200 g of water. (Kb for water =

0.512 K kg mol1, Molar mass of CaCl2 = 111 g mol1)

OR

(a) Define the following terms :

(i) Azeotrope

(ii) Osmotic pressure

(iii) Colligative properties

(b) Calculate the molarity of 9.8% (w/w) solution of H2SO4 if the density

of the solution is 1.02 g ml1. (Molar mass of H2SO4 = 98 g mol1)

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56/2/1 13 P.T.O.

29. (a) {ZZ Ho$ H$maU ~VmBE : 3

(i) + 5 AdWm _| Bi ~b CnMm`H$ hmoVm h &

(ii) PCl5 Vmo OmZm OmVm h naVw NCl5 Zht &

(iii) bmh HCl _| KwbH$a FeCl2 ~ZmVm h, FeCl3 Zht &

(b) {ZZ H$s gaMZmE ~ZmBE : 2

(i) XeOF4

(ii) HClO4

AWdm

(a) {ZZ H$s gaMZmE ~ZmBE : 2

(i) H2S2O8

(ii) bmb P4

(b) {ZZ Ho$ H$maU {b{IE : 3

(i) dmn AdWm _| JYH$ (g\$a) AZwMw~H$d X{eV H$aVm h &

(ii) OrZmZ go {^, hr{b`_ H$m H$moB nQ amgm`{ZH$> `m{JH$ kmV Zht h &

(iii) H3PO3 go H3PO2 EH$ A{YH$ ~b AnMm`H$ h &

(a) Account for the following :

(i) Bi is a strong oxidizing agent in the + 5 state.

(ii) PCl5 is known but NCl5 is not known.

(iii) Iron dissolves in HCl to form FeCl2 and not FeCl3.

(b) Draw the structures of the following :

(i) XeOF4

(ii) HClO4

OR

(a) Draw the structures of the following :

(i) H2S2O8

(ii) Red P4

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56/2/1 14

(b) Account for the following :

(i) Sulphur in vapour state exhibits paramagnetism.

(ii) Unlike xenon, no distinct chemical compound of helium is

known.

(iii) H3PO2 is a stronger reducing agent than H3PO3.

30. (a) EoWoZb Ho$ {ZZ A{^H$maH$m| Ho$ gmW A{^{H$`m H$aZo na ~Zo CnmXm| H$mo {b{IE : 3

(i) CH3MgBr go Ama {\$a H3O+ go

(ii) Zn-Hg/gm HCl go

(iii) VZw NaOH H$s CnpW{V _| C6H5CHO go

(b) {ZZ `m{JH$ `w_mo _| nana ^oX H$aZo Ho$ {bE gab amgm`{ZH$ narjU Xr{OE : 2

(i) ~oOmoBH$ Ab Ama E{Wb ~oOmoEQ>

(ii) monoZb Ama `yQ>oZ-2-AmoZ

AWdm

(a) {ZZ Ho$ H$maU {b{IE : 2

(i) HCN Ho$ gmW A{^{H$`m H$aZo _| CH3COCH3 go CH3CHO A{YH$ A{^{H$`merb hmoVm h &

(ii) go_rH$m~oOmBS> (H2NNHCONH2) _| Xmo NH2 Jwn hmoVo h & {\$a ^r go_rH$m~mOmoZ ~ZmZo _| Ho$db EH$ NH2 Jwn {H$`mH$mar hmoVm h &

(b) {ZZ Zm_Ymar A{^{H$`mAmo Ho$ {bE amgm`{ZH$ g_rH$aU {b{IE : 3

(i) amoOoZ_wS A{^{H$`m

(ii) hob-dmobmS>-Oo{bH$s A{^{H$`m

(iii) H$ZrOmamo A{^{H$`m

(a) Write the products formed when ethanal reacts with the following

reagents :

(i) CH3MgBr and then H3O+

(ii) Zn-Hg/conc. HCl

(iii) C6H5CHO in the presence of dilute NaOH

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56/2/1 15 P.T.O.

(b) Give simple chemical tests to distinguish between the following

pairs of compounds :

(i) Benzoic acid and Ethyl benzoate

(ii) Propanal and Butan-2-one

OR

(a) Account for the following :

(i) CH3CHO is more reactive than CH3COCH3 towards reaction

with HCN.

(ii) There are two NH2 groups in semicarbazide

(H2NNHCONH2). However, only one is involved in the

formation of semicarbazone.

(b) Write the chemical equation to illustrate each of the following

name reactions :

(i) Rosenmund reduction

(ii) Hell-Volhard-Zelinsky reaction

(iii) Cannizzaro reaction

2,800

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1MARKING SCHEMEChemistry 2014

FOREIGN SET (56/2/1)1 Collectors enhance non-wettability of the mineral/ore particles 12 van der Waals forces 13 Because of high inter-electronic repulsion of non bonding electrons owing to the small

bond length / atomic size1

4 Coordination isomerism 15 r=34 a or 4r =3 a 16 2 hydroxybenzaldehyde 17 CH3 NH2 ,because of the electron releasing (+I effect) tendency of methyl group +8 Amylose and amylopectin 19 m= z I t I=5 A t= 20 x 60s = 1200s

m= atomic massn x F x I x tm= .2 x 96500 C x 5 A x 1200 sm= 1.825 g (or any other suitable method)

1

10 Half-life of a reaction is the time in which the concentration of a reactant is reduced tohalf of its initial concentration.

(i) (ii)

1

+

11 4Ag + 8 CN- + 2H2O + O2 4 [Ag(CN)2] - + 4 OH-2[Ag(CN)2] - + Zn [Zn(CN)4] - 2 + 2Ag

OrAg2S + 4NaCN 2 Na[Ag(CN)2] + Na2S2Na[Ag(CN)2] + Zn Na2 [Zn(CN)4] + 2Ag(balancing of equation is not necessary)

11

12 Rhombic and MonoclinicRhombic SulphurRhombic sulphur changes to monoclinic sulphur

1

OR12 a) High pressure and low temperature

b) Because ionization of HSO-4 is difficult / removal of proton from negativelycharged HSO-4 is difficult.

11

13 (i)(ii)

11

14 Hydridization : sp3d2 shape octahedralIUPAC hexafluoridocobaltate(III)

+1

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215 (i) CH3 CH2- Cl + KOH (aq) CH3CH2OH +KCl(ii)

1

1

16 a) 1-Bromobutane / CH3 CH2CH2 CH2BrBecause it is a primary alkyl halide

b) Because carbocation formed in SN1 reaction is sp2 hybridized and planar.

+

117 HBr H+ + Br-

Or

( where R = -CH3)

1

18 (i) Br2 / H2O or aq. Br2(ii) LiAlH4or NaBH4 or H2 / Ni (or any other)(iii) R Cl and anhyd . Al Cl3(iv) Acidic or alkaline KMnO4, K2Cr2 O7 (acidic)

x4=2

19 (i) Schottky defect, due to similar size of K+ and Cl- ion(ii) n-type(iii) CO2(iv) Ferromagnetic

+1

20 a)(i) The fuel cell runs continuously as long as the reactants are supplied(ii) Highly efficient(iii) Pollution free

(any two)b) log Kc = nE0cell0.059

log Kc = 2xE0cell0.059

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3log 10 =2xE0cell0.059 [log 10 = 1]E0cell = 0.0592 = 0.0295 V

121 SO2 Cl2 SO2 + Cl2

At t = 0s 0.4 atm 0 atm 0 atmAt t = 100s (0.4 x) atm x atm x atmPt = 0.4 x + x + xPt = 0.4 + x

0.7 = 0.4 + xx = 0.3

k = 2.303t logk = 2.303t log 0.40.8-0.7k = 2.303100 log 0.40.1k = . x 0.6021 = 1.39 x 10-2 s-1

1

1

122 a) = k p1/n or log (x/m)= log k + 1/n log p

b) Dispersed phase = liquid Dispersion medium = Solidc) Because of coagulation of colloidal particles

111

23 a) +3 +2 +4 oxidation statesb) Transition elements

(i) Form coloured compounds(ii) Form complexes(iii) Act as catalysts(iv) Paramagnetic(v) Form alloys(vi) Form interstitial compounds (any two)Or any other

c) Zn, because of fully filled d orbitals

1

+

+OR

23 a) Because of stable half filled orbitals (3d5)b) Because Zn has no unpaired electrons in d orbitals.c) Because of the presence of one unpaired electron in Ti3+ whereas there is no

unpaired electron in Sc+3

111

24 (i) A = CH3CN B = CH3CH2NH2 C = CH3CH2OH(ii) A = CH3 CONH2 B = CH3NH2 C = CH3NC

++++

25 (i) Anomers are the isomers which differ only in the configuration of hydroxylgroup at C-1 of glucoseOr

1

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4 and forms of glucose are called anomers(ii) Denaturation of proteins when native protein is subjected to physical or

chemical change, it loses its biological activity and is called denaturation.(iii) Essential amino acids are the amino acids required in our diet for the growth

of the body / which are not synthesized by our body and obtained throughdiet.

1

1

26 (i) The drugs which are used to prevent the interaction of histamine with thereceptors present in the stomach wall. Eg. Cimetidine / Ranitidine /Dimetapp (or any other)

(ii) Chloramphenicol(iii) Because it is unstable at cooking temperature

+

11

27 (i) Concern towards environment / caring / socially aware / team work. (atleasttwo values)(ii) Polymers which can be degraded by the action of microorganisms. Eg. PHBV, Nylon -2-nylon- 6/ any natural polymer(iii) Homo polymer

1

+

128 (i) Raoults law : state that for a solution containing volatile components, the

partial vapour pressure of each component is directly proportional to itsmole fraction.Ideal solution.

(ii) Tb = i Kb xWcacl2Mcacl2 x= 3x0.512 K kg mol-1x x 1000200 kg= 0.69K or 0.690C

1

1

1

1

1OR

28 a)(i) Azeotrope is a liquid mixture which boils at constant temperature with

constant composition.(ii) Osmotic pressure : is the pressure applied on the solution side to stop the

flow of solvent across the semi permeable membrane from lowerconcentration of the solution to higher concentration.

(iii) Colligative properties : are the properties of solution which depend upon theno of moles of solute or concentration of solute and not on the nature ofsolute.

b) M =V(L)= x 1000V( ) (B Solute)M = . x x 1.02M = 1.02M

1

1

1

1

29 a) (i) Because Bi is more stable in +3 oxidation state.(ii) Because of the availability to d orbital in P which is not in N/ nitrogen cannot

extend its covalency beyond 4(iii) Because of the formation of H2(g) which prevents the oxidation of Fe+2 to Fe+3 /

HCl is only a mild oxidising agent1x3=3

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5a) (i) (ii)1+1

OR29 a) (i)

(ii)

Polymericb)(i) Because of the presence of two unpaired electrons .(ii) Because of high ionization enthalpy of He.(iii) Because of the presence of two P-H bonds in H3PO2 whereas in H3PO3

one P-H bond is present.

1

1

1

1

1

30 a)(i)CH3-CHO CH3MgBr CH3CH(CH3)- OMgBr H3O+ CH3CH(OH)- CH3

(ii) CH3CHO Zn-Hg CH3-CH3Conc HCl

(iii) C6H5CHO + CH3-CHO dil NaOH C6H5CH(OH) CH2CHO(Award full marks even if only products are given)

b) (i) Add NaHCO3, benzoic acid will give brisk effervescence whereas ethyl benzoate willnot give this test. (or any other test)(ii) Add tollens reagent , propanal will give silver mirror whereas Butan-2-one will notgive this test. (or any other test)

1

1

1

1

1

OR

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30 a) (i) Because the positve charge on carbonyl carbon of CH3 CHO decreases to a lesserextent due to one electron releasing (+I effect) CH3 group as compared to CH3 COCH3(two electron releasing CH3groups) and hence more reactive.(ii) because one of the NH2 is involved in resonance with carbonyl group and henceacquires positive charge.(b) (i)

(ii)

(iii)

(or any other suitable reaction)

1

1

1

1

1

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CBSE.pdf56-2-1 CHEMISTRY.pdfMARKING SCHEME_Foreign _ SET 1.pdf