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CBSE Class 12 Board Exam 2020 : Chemistry (Series 3)

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H$moS> Z . Code No. amob Z . 56/3/1 narjmWu H$moS >H$mo C ma-nwp VH$m Ho$ _wI-n >na Ad ` {bIo & Roll No. Candidates must write the Code on the title page of the answer-book. (I) ZmoQ> H $n`m Om M H$a b| {H$ Bg Z-n _o _w{ V n > 19 h & (II) Z-n _| Xm{hZo hmW H$s Amoa {XE JE H$moS >Z ~a H$mo N>m C ma-nwp VH$m Ho$ _wI-n > na {bI| & (III) H $n`m Om M H$a b| {H$ Bg Z-n _| >37 Z h & H $n`m Z H$m C ma {bIZm ew $ H$aZo go nhbo, C ma-nwp VH$m _| Z H$m H $_m H$ Ad ` {bI| & Bg Z-n H$mo n T>Zo Ho$ {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 n T>|Jo Am a Bg Ad{Y Ho$ Xm amZ do C ma-nwp VH$m na H$moB C ma Zht {bI|Jo & (IV) (V) NOTE (I) Please check that this question paper contains 19 printed pages. (II) 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. (III) Please check that this question paper contains 37 questions. (IV) Please write down the Serial Number of the question in the answer-book before attempting it. (V) 15 minute 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. agm`Z {dkmZ (g mp VH$) CHEMISTRY (Theory) {ZYm [aV g_` : 3 K Q>o A{YH$V_ A H$ : 70 Time allowed : 3 hours .56/3/1 Maximum Marks : 70 1 P.T.O. gm_m ` {ZX}e : {Z Z{b{IV {ZX}em| H$mo ~h V gmdYmZr go n{ T>E Am a CZH$m g Vr go nmbZ H$s{OE (i) (ii) (iii) (iv) (v) (vi) (vii) (viii) : `h Z-n Mma I S>m| _| {d^m{OV {H$`m J`m h H$, I, J Ed K & Bg Z-n _| 37 Z h & g^r Z A{Zdm` h & I S> H$ _| Z g `m 1 go 20 VH$ A{V bKw-C mar` H$ma Ho$ Z h , `oH$ Z 1 A H$ H$m h & `oH$ Z H$m C ma EH$ e X `m EH$ dm ` _| Xr{OE & I S> I _| Z g `m 21 go 27 VH$ bKw-C mar` H$ma Ho$ Z h , `oH$ Z 2 A H$m| H$m h & I S> J _| Z g `m 28 go 34 VH$ XrK -C mar` H$ma-I Ho$ Z h , `oH$ Z 3 A H$m| H$m h & I S> K _| Z g `m 35 go 37 VH$ XrK -C mar` H$ma-II Ho$ Z h , `oH$ Z 5 A H$m| H$m h & Z-n _| H$moB g_J {dH$ n Zht h & VWm{n, Xmo-Xmo A H$m| Ho$ Xmo Zm| _|, VrZ-VrZ A H$m| Hoo$ Xmo Zm| _| VWm nm M-nm M A H$m| Ho$ VrZm| Zm| _| Am V[aH$ {dH$ n {X`m J`m h & Eogo Zm| _| go Ho$db EH$ hr {dH$ n H$m C ma Xr{OE & BgHo$ A{V[a $, Amd `H$VmZwgma, `oH$ I S> Am a Z Ho$ gmW `Wmo{MV {ZX}e {XE JE h & Ho$ Hw$boQ>a AWdm bm J Q>o~b Ho$ `moJ H$s AZw_{V Zht h & I S> H$ {XE JE AZw N>oX H$mo n{ T>E VWm Z g `m 1 go 5 Ho$ C ma Xr{OE : 1 5=5 AmdV gmaUr Ho$ d- bm H$ | dJ 3 go 12 Ho$ V d AmVo h Omo g H $ U V dm| Ho$ $n | OmZo OmVo h & gm m $n go BZ V dm| H$m Bbo Q >m {ZH$ {d mg (n 1) d1 10 ns1 2 h & BZ na mUwAm| Ho$ Cnm {V D$Om Va Ho$ d-H$jH$m| | Bbo Q >m Z ^ao OmVo h VWm Bg H$ma g H $ U YmVwAm| H$s VrZ n { V m AWm V 3d, 4d d 5d loUr m V hmoVr h & VWm{n Zn, Cd Am a Hg H$mo g H $ U V d Zht mZm OmVm h & g H $ U V d Hw$N> A{^bmj{UH$ JwU Xem Vo h O go n[adV Zr` Am grH$aU Ad WmE , g Hw$b {Z m U, a JrZ Am Zm| Am a { lmVwAm| H$m ~ZZm, C oaH$s g{H $ Vm Am{X & g H $ U YmVwE (Zn, Cd Am a Hg Ho$ AndmXm| Ho$ gmW) H$R>moa hmoVr h Am a BZHo$ JbZm H$ C M hmoVo h & .56/3/1 2 General Instructions : Read the following instructions very carefully and strictly follow them : (i) This question paper comprises four Sections A, B, C and D. There are 37 questions in the question paper. All questions are compulsory. (ii) Section A Questions no. 1 to 20 are very short answer type questions, carrying 1 mark each. Answer these questions in one word or one sentence. (iii) Section B Questions no. 21 to 27 are short answer type questions, carrying 2 marks each. (iv) Section C Questions no. 28 to 34 are long answer type-I questions, carrying 3 marks each. (v) Section D Questions no. 35 to 37 are long answer type-II questions, carrying 5 marks each. (vi) There is no overall choice in the question paper. However, an internal choice has been provided in 2 questions of two marks, 2 questions of three marks and all the 3 questions of five marks. You have to attempt only one of the choices in such questions. (vii) In addition to this, separate instructions are given with each section and question, wherever necessary. (viii) Use of calculators and log tables is not permitted. SECTION A Read the given passage and answer the questions number 1 to 5 that follow : 1 5=5 The d-block of the periodic table contains the elements of the groups 3 12 and are known as transition elements. In general, the electronic configuration of these elements is (n 1) d1 10 ns1 2. The d-orbitals of the penultimate energy level in their atoms receive electrons giving rise to the three rows of the transition metals i.e., 3d, 4d and 5d series. However, Zn, Cd and Hg are not regarded as transition elements. Transition elements exhibit certain characteristic properties like variable oxidation states, complex formation, formation of coloured ions and alloys, catalytic activity, etc. Transition metals are hard (except Zn, Cd and Hg) and have a high melting point. .56/3/1 3 P.T.O. 1. Zn, Cd Am a Hg g H $ U 2. 3d loUr 3. g H $ U YmVwE Am a CZHo$ m {JH$ C oaH$s g{H $ Vm m| Xem Vo h 4. g H $ U YmVwAm| Ho$ JbZm H$ C M m| hmoVo h 5. Obr {db Z | V d m| Zht mZo OmVo h ? H$m H$m Z-gm g H $_U YmVw n[adV Zr Am grH$aU Ad WmE Zht Xem Vm h Cu2+ Am Z ? ? ? a JrZ m| hmoVm h O~{H$ Zn2+ Am Z a JhrZ hmoVm h & Z g `m 6 go 10 EH$ e X C mar h : 1 5=5 6. Anmobmo A V[aj H$m H $ | moJ | bmE JE gob H$m Zm {b{IE & 7. 1 mob H2O H$mo O2 | 8. {H$gr W H$mo{Q> H$s A{^{H $ m Ho$ {bE g Ho$ gmW J m $ Ho$ T>mb H$m _mZ {b{IE & 9. Cg S>mBg Ho$amBS> H$m Zm {b{IE Omo Ob-AnKQ>Z na byH$mog Ho$ Xmo AUw XoVm h & 10. X V OZ | B Vo mb {H$E OmZo dmbo g p b Q> An mO H$ Ho$ dJ H$m Zm {b{IE & Am grH $V H$aZo Ho$ {bE {H$VZo Hy$bm H$s Amd H$Vm hmoVr h ln[R] Ho$ {dMaU H$mo Xem Zo dmbo Z g `m 11 go 15 ~h {dH$ nr Z h : 11. 12. 1 5=5 {Z Z{b{IV | go {H$gH$m emoYZ S>b n[a H$aU {d{Y mam hmoVm h (A) (B) Cu Zn (C) (D) Ge Sn ao{g_rH$aU hmoVm h (A) SN2 A{^{H $ m | (B) SN1 A{^{H $ m | (C) Z Vmo SN2 A{^{H $`m | Am a Z hr SN1 A{^{H $ m | (D) SN2 A{^{H $ m Am a SN1 A{^{H $ m XmoZm| | .56/3/1 ? 4 ? 1. Why are Zn, Cd and Hg non-transition elements ? 2. Which transition metal of 3d series does not show variable oxidation states ? 3. Why do transition metals and their compounds show catalytic activity ? 4. Why are melting points of transition metals high ? 5. Why is Cu2+ ion coloured while Zn2+ ion is colourless in aqueous solution ? Questions number 6 to 10 are one word answers : 1 5=5 6. Name the cell which was used in the Apollo Space Programme. 7. How many coulombs are required for the oxidation of 1 mol of H2O to O2 ? 8. Write the slope value obtained in the plot of ln[R] vs. time for a first order reaction. 9. Name the disaccharide which on hydrolysis gives two molecules of glucose. 10. Name the class of the synthetic detergent which is used in toothpaste. Questions number 11 to 15 are multiple choice questions : 11. 12. 1 5=5 Which of the following is refined by the zone refining process ? (A) Cu (B) Zn (C) Ge (D) Sn Racemisation occurs in (A) SN2 reaction (B) SN1 reaction (C) Neither SN2 nor SN1 reactions (D) SN2 reaction as well as SN1 reaction .56/3/1 5 P.T.O. 13. CHCl3 Am a 14. m {JH$ CrCl3 . 6H2O H$m EH$ mob AgNO3 {db Z Ho$ Am{Y Ho$ gmW A{^{H $ m H$aHo$ AgCl (s) Ho$ Xmo mob ~ZmVm h & m {JH$ H$m g aMZm H$ gy h 15. Eo H$mohm br XoZo dmbm nXmW h KOH Ho$ CH2 NH2 H$mo gmW (A) [Cr(H2O)5 Cl] Cl2 . H2O (B) [Cr(H2O)3 Cl3] . 3H2O (C) [Cr(H2O)4 Cl2] Cl . 2H2O (D) [Cr(H2O)6] Cl3 J H$aZo na ~Zm X J Y no Q>mBS> ~ Y Cnp WV hmoVm h (A) H$m~m}hmBS >oQ>m| | (B) {dQ>m{ Zm| | (C) moQ>rZm| | (D) a~a | Z g `m 16 go 20 Ho$ {bE, Xmo H$WZ {XE JE h {OZ_| EH$ H$mo A{^H$WZ (A) VWm X gao H$mo H$maU (R) mam A {H$V {H$`m J`m h & BZ Zm| Ho$ ghr C ma ZrMo {XE JE H$moS>m| (i), (ii), (iii) Am a (iv) _| go MwZH$a Xr{OE : 1 5=5 (i) (ii) (iii) (iv) .56/3/1 A{^H$WZ (A) Am a H$maU (R) XmoZm| ghr H$WZ h Am a H$maU (R), A{^H$WZ (A) H$s ghr m m h & A{^H$WZ (A) Am a H$maU (R) XmoZm| ghr H$WZ h , na Vw H$maU (R), A{^H$WZ (A) H$s ghr m m Zht h & A{^H$WZ (A) ghr h , na Vw H$maU (R) JbV H$WZ h & A{^H$WZ (A) JbV h , na Vw H$maU (R) ghr H$WZ h & 6 13. CH2 NH2 on heating with CHCl3 and alcoholic KOH gives foul smell of 14. 15. One mole of CrCl3 . 6H2O compound reacts with excess AgNO3 solution to yield two moles of AgCl (s). The structural formula of the compound is (A) [Cr(H2O)5 Cl] Cl2 . H2O (B) [Cr(H2O)3 Cl3] . 3H2O (C) [Cr(H2O)4 Cl2] Cl . 2H2O (D) [Cr(H2O)6] Cl3 Peptide linkage is present in (A) Carbohydrates (B) Vitamins (C) Proteins (D) Rubber For questions number 16 to 20, two statements are given one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (i), (ii), (iii) and (iv) as given below : 1 5=5 (i) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A). (ii) Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A). (iii) Assertion (A) is correct, but Reason (R) is incorrect statement. (iv) Assertion (A) is incorrect, but Reason (R) is correct statement. .56/3/1 7 P.T.O. 16. A{^H$WZ (A) : gm Vm KQ>Zo Ho$ gmW {d wV -AnKQ> H$s MmbH$Vm KQ>Vr h & H$maU (R) : VZwH$aU H$aZo na {V BH$mB Am VZ | Am Zm| H$s g m ~ T>Vr h & 17. A{^H$WZ (A) : Eo H$mohm bm| | H$maU (R) : 18. Am~ Y H$moU MVw $bH$s H$moU go Oam gm H$ hmoVm h & Am grOZ na Xmo EH$mH$s Bbo Q >m Z w Ho$ ~rM {VH$fu A V:{H $ m Ho$ H$maU hmoVm h & A{^H$WZ (A) : g Hw$b H$maU (R) : C O H [Pt(NH3)4 Cl2]2+ H$s Anojm g Hw$b [Pt(en)2 Cl2]2+ H$ Wm r hmoVm h & g Hw$b [Pt(en)2 Cl2]2+ H$sboQ> ^md Xem Vm h & 19. A{^H$WZ (A) : namgaU Xm~ EH$ AUwg JwUY h & H$maU (R) : namgaU Xm~ mobaVm Ho$ AZwH $ mZwnmVr hmoVm h & 20. A{^H$WZ (A) : Eop S>hmBS>m| H$s Anojm H$sQ>moZm| H$s A{^{H $ merbVm A{YH$ hmoVr h & H$maU (R) : Eop S>hmBS>m| H$s VwbZm | H$sQ>moZm| | H$m~m}{Zb H$m~ Z H$ Bbo Q >m ZamJr hmoVm h & I S> I 21. Xr JB A{^{H $ m A + 3B 2C |, C Ho$ ~ZZo H$m doJ 2 5 10 4 mol L 1 s 1 h & n[aH${bV H$s{OE : (i) A{^{H $ m H$m doJ, Am a (ii) B Ho$ bw V hmoZo H$m doJ & 22. {Z Z{b{IV H$s ^y{ H$m {b{IE : (i) Eobw{ {Z Ho$ {Z H$f U | NaAlF4 H$s (ii) Ni Ho$ emoYZ | CO H$s AWdm ~m gmBQ> A H$ Ho$ {ZjmbZ mam ew Eobw{ Zm m V H$aZo go g ~ amgm {ZH$ g rH$aU| {b{IE & .56/3/1 8 2 1 1 2 16. Assertion (A) : Conductivity of an electrolyte decreases with decrease in concentration. Reason (R) : 17. Assertion (A) : The C O H bond angle in alcohols is slightly less than the tetrahedral angle. Reason (R) : 18. Number of ions per unit volume increases on dilution. This is due to the repulsive interaction between the two lone electron pairs on oxygen. Assertion (A) : [Pt(en)2 Cl2]2+ complex [Pt(NH3)4 Cl2]2+ Reason (R) : 19. less stable than complex. [Pt(en)2 Cl2]2+ complex shows chelate effect. Assertion (A) : Osmotic pressure is a colligative property. Reason (R) : 20. is Osmotic pressure is directly proportional to molarity. Assertion (A) : Reactivity of ketones is more than aldehydes. Reason (R) : The carbonyl carbon of ketones is less electrophilic as compared to aldehydes. SECTION B 21. In the given reaction A + 3B 2C, the rate of formation of C is 2 5 10 4 mol L 1 s 1. Calculate the 22. (i) rate of reaction, and (ii) rate of disappearance of B. 2 Write the role of the following : (i) NaAlF4 in the extraction of Aluminium 1 (ii) CO in the refining of Ni OR 1 Write the chemical equations involved in the leaching of bauxite ore to prepare pure alumina. .56/3/1 9 2 P.T.O. 23. 2 ^m {VH$ A{YemofU Am a agmoemofU Ho$ ~rM Xmo A Va {b{IE & AWdm oH$ Ho$ {bE Cn w V CXmhaU g{hV {Z Z{b{IV nXm| H$mo n[a^m{fV H$s{OE 24. (i) ghMmar H$mobm BS> (ii) O/W B eZ (a) g Hw$b (b) g Hw$b 2 (nm g) [CoF6]3 H$m ({X m J`m h : : Co H$m AmB y nr E gr Zm Am a g H$aU {b{IE & na mUw H $ m H$ [Co(en)2 Cl2]2+ = 27) mam {H$g H$ma H$s g md dVm Xem B OmVr h ? g Hw$b Ho$ Cg g md d H$s g aMZm H$m Zm {b{IE Omo Y wdU KyU H$ hmo & 25. 26. 27. H$maU Xr{OE : Xm T>r ~ZmZo Ho$ gm~wZ | p bgam b hmoVm h & (ii) {VA bm| H$m Cn moJ A{YH$ g VH$ Zht H$aZm Mm{hE & (i) Amo{bJmog Ho$amBS> (ii) And V eH $am 2 2 (i) {Z Z{b{IV nXm| H$s n[a^mfm {b{IE Bg : 2 {Z Z{b{IV A{^{H $ m Ho$ C nmXm| H$mo {b{IE : 6 XeF4 + 12 H2O m h A{^{H $ m Ag mZwnmVZ A{^{H $ m h ? AnZo C ma Ho$ g W Z | H$maU Xr{OE & .56/3/1 10 2 23. Write two differences between physisorption and chemisorption. 2 OR Define the following terms with a suitable example of each : 24. 2 (i) Associated colloids (ii) O/W emulsion (a) Write the IUPAC name and hybridisation of the complex [CoF6]3 . (Given : Atomic number of Co = 27) (b) What type of isomerism is shown by the complex [Co(en)2 Cl2]2+ ? Name the structure of an isomer of this complex which is optically active. 25. 26. 27. 2 Give reasons : 2 (i) Shaving soaps contain glycerol. (ii) Antacids should not be used for longer time. Define the following terms : (i) Oligosaccharides (ii) Invert sugar 2 Write the products of the following reaction : 6 XeF4 + 12 H2O Is this reaction a disproportionation reaction ? Give reasons in support of your answer. .56/3/1 2 11 P.T.O. I S> J 28. 298 K na Xr JB A{^{H $ m Ho$ {bE A{YH$V H$m Am a log Kc n[aH${bV H$s{OE : 3 Ni (s) + 2 Ag+ (aq) Ni2+ (aq) + 2 Ag (s) {X m J`m h : = 0 25 V, Eo = + 0 80 V Eo 2 Ni / Ni Ag / Ag 1 F = 96500 C mol 1 29. {H$gr W H$mo{Q> H$s A{^{H $ m H$mo 40% nyU hmoZo | 80 { ZQ> bJVo h & doJ p Wam H$ (k) H$m mZ n[aH${bV H$s{OE & {H$VZo g | A{^{H $ m 90% nyU hmoJr ? [ {X`m J`m h : log 2 = 0 3010, log 3 = 0 4771, log 4 = 0 6021, log 5 = 0 6771, 3 log 6 = 0 7782] 30. {Z Z{b{IV ~h bH$m| | EH$bH$m| Ho$ Zm Am a g aMZmE {b{IE (i) yZm-S (ii) ZmBbm Z-6,6 (iii) ~ Ho$bmBQ> 31. {Z Z{b{IV A{^{H $ mAm| Ho$ w C nmX/C nmXm| H$mo {b{IE .56/3/1 12 : : 3 3 SECTION C 28. Calculate the maximum work and log Kc for the given reaction at 298 K : 3 Ni (s) + 2 Ag+ (aq) Ni2+ (aq) + 2 Ag (s) Given : = 0 25 V, Eo = + 0 80 V Eo 2 Ag / Ag Ni / Ni 1 F = 96500 C mol 1 29. A first order reaction is 40% complete in 80 minutes. Calculate the value of rate constant (k). In what time will the reaction be 90% completed ? 3 [Given : log 2 = 0 3010, log 3 = 0 4771, log 4 = 0 6021, log 5 = 0 6771, log 6 = 0 7782] 30. 31. Write the names and structures of the monomers in the following polymers : (i) Buna-S (ii) Nylon-6,6 (iii) Bakelite Write the major product(s) of the following reactions : .56/3/1 13 3 3 P.T.O. 32. (a) {Z Z{b{IV A{^{H $ m H$s {H $ m{d{Y {b{IE : H 2 CH3CH2OH CH3CH2OCH2CH3 + H2O 413 K (b) 2+1=3 y rZ go \$sZm b H$m {daMZ {b{IE & AWdm Amn {Z Z{b{IV n[adV Z H $go g n H$a|Jo : 33. 34. 3 (i) gmo{S> $sZm gmBS> go o-hmBS >mo gr~o OmoBH$ A b (ii) EogrQ>moZ go monrZ (iii) \$sZm b go bmoamo~o OrZ {Z{ V C nmXm| H$mo {b{IE O~ A{^{H $ m H$aVm h : (i) VZw NaOH H$s (ii) HCN (iii) gm (CH3)3 C CHO Cnp W{V | {Z Z{b{IV A{^H$ H$m| Ho$ gmW 3 CH3COCH3 NaOH oH$ Ho$ {bE Cn w V CXmhaU XoH$a d{damJr Am a damJr gm b H$mo n[a^m{fV H$s{OE & d{damJr gm b H$s VwbZm | damJr gm b H$m H $XZ H${R>Z m| hmoVm h ? AWdm {Z Z{b{IV nXm| H$mo n[a^m{fV H$s{OE : (i) AmH$ma-daUm H$ C oaU (ii) H $m Q> Vmn (iii) no Q>Z (no Q>mB OoeZ) 3 3 I S> K 35. (a) .56/3/1 H$maU Xr{OE : (i) OrZm Z H$s ^m {V hr{b m {JH$ Zht ~ZmVr & (ii) HOCl H$s Anojm HClO4 ~bVa A b h & (iii) J YH$ EH$ ~h na mUwH$ R>mog h O~{H$ Am grOZ { na mUwH$ J g h & 14 3 32. (a) Write the mechanism of the following reaction : H 2 CH3CH2OH CH3CH2OCH2CH3 + H2O 413 K (b) Write the preparation of phenol from cumene. OR 2+1=3 How can you convert the following : 33. (i) Sodium phenoxide to o-hydroxybenzoic acid (ii) Acetone to propene (iii) Phenol to chlorobenzene 3 Write the products formed when (CH3)3 C CHO reacts with the following reagents : 34. 3 (i) CH3COCH3 in the presence of dilute NaOH (ii) HCN (iii) Conc. NaOH Define Lyophobic and Lyophilic sol with a suitable example of each. Why is coagulation of Lyophilic sol difficult as compared to Lyophobic sol ? OR 3 Define the following terms : 3 (i) Shape-selective catalysis (ii) Kraft temperature (iii) Peptization SECTION D 35. (a) Give reasons : 3 (i) Helium does not form compounds like Xenon. (ii) HClO4 is a stronger acid than HOCl. (iii) Sulphur is a polyatomic solid whereas Oxygen is a diatomic gas. .56/3/1 15 P.T.O. (b) (a) (b) (c) 36. (a) (b) (a) (b) (c) h Xem Zo Ho$ {bE {H$ gm H2SO4 (i) Am grH$maH$, Ed (ii) {ZO bZ H$_ H$ H$s ^m {V H$m H$aVm h , oH$ Ho$ {bE CXmhaU Ho$ $n _| EH$-EH$ A{^{H $ m {b{IE & AWdm {Z Z{b{IV Ho$ {bE H$maU Xr{OE : (i) Cl Am Z H$s Anojm F Am Z H$s Ob moOZ E W nr A{YH$ hmoVr h & (ii) dJ -16 Ho$ Am gmBS>m| | SO2 EH$ AnMm H$ h , O~{H$ TeO2 EH$ Am grH$maH$ h & F2 H$s Ob Ho$ gmW A{^{H $ m {b{IE & Am moS>rZ (I2) Ob Ho$ gmW A{^{H $ m m| Zht H$aVr ? XeF2 H$s g aMZm ~ZmBE & H$maU Xr{OE : (i) {n NH2 g yh Bbo Q >m ZamJr {V WmnZ A{^{H $ mAm| | Am Wm} Ed n am {ZX}eH$ hmoVm h { $a ^r Eo{ZbrZ ZmBQ >moH$aU mam Wo Q> _m m | oQ>m-ZmBQ >moEo{ZbrZ XoVr h & (ii) Obr {db Z | (CH3)3 N H$s Anojm (CH3)2 NH A{YH$ jmaH$s hmoVm h & (iii) ew mW{ H$ Eo rZm| Ho$ {daMZ Ho$ {bE Eop H$b h bmBS>m| H$m Eo moZr-AnKQ>Z EH$ A N>r {d{Y Zht h & {Z Z{b{IV Ho$ {d^oX H$s{OE : (i) CH3CH2NH2 Am a (CH3CH2)2 NH (ii) Eo{ZbrZ Am a CH3NH2 AWdm {Z Z{b{IV A{^{H $ mAm| | A Am a B H$s g aMZmE {b{IE : H 2O / H CuCN A B (i) C6H5 N 2 Cl (ii) NH3 NaOBr A B CH3COOH o{Wb Eo_rZ H$s ~o Om b bmoamBS> Ho$ gmW amgm {ZH$ A{^{H $ m {b{IE Am a m V C nmX H$m AmB y nr E gr Zm {b{IE & {Z Z{b{IV H$mo CZHo$ pKb mZm| Ho$ ~ T>Vo h E H $ | dp WV H$s{OE : C6H5NH2, NH3, C2H5NH2, (C2H5)2 NH .56/3/1 16 2 1 1 1+1 1 3 2 1 1 1+1 1 (b) Write one reaction as an example of each, to show that conc. H2SO4 acts as (i) (ii) (a) an oxidising agent, and a dehydrating agent. OR Account for the following : (i) (ii) 36. 2 Hydration enthalpy of F ion is more than Cl ion. SO2 is a reducing agent, whereas TeO2 is an oxidising agent 1 in group-16 oxides. 1 (b) Write the reaction of F2 with water. Why does I2 not react with water ? 1+1 (c) Draw the structure of XeF2. 1 (a) Give reasons : (i) Although NH2 group is o/p directing in electrophilic substitution reactions, yet aniline, on nitration gives good yield of m-nitroaniline. (ii) (CH3)2 NH is more basic than (CH3)3 N in an aqueous solution. (iii) Ammonolysis of alkyl halides is not a good method to prepare pure primary amines. 3 (b) Distinguish between the following : (i) CH3CH2NH2 and (CH3CH2)2 NH 2 (ii) (a) Aniline and CH3NH2 OR Write the structures of A and B in the following reactions : (i) H O /H CuCN C6H5 N 2 Cl A 2 B 1 (ii) NH3 NaOBr A B CH3COOH 1 (b) Write the chemical reaction of methyl amine with benzoyl chloride and write the IUPAC name of the product obtained. 1+1 (c) Arrange the following in the increasing order of their pKb values : 1 C6H5NH2, NH3, C2H5NH2, (C2H5)2 NH .56/3/1 17 P.T.O. 37. (a) (b) (a) (b) {H$gr {db Z | 5 85 g NaCl ( moba mZ = 58 5 g mol 1) {V brQ>a {db Z {d mZ h & BgH$m 27 C na namgaU Xm~ 4 75 dm w S>b (atm) h & Bg {db Z | NaCl H$s {d moOZ m m n[aH${bV H$s{OE & ({X m J`m h : R = 0 082 L atm K 1 mol 1) hoZar {Z {b{IE & JmoVmImoam| mam w V dm w H$mo hr{b go VZwH$aU H$aHo$ Q> H$m| | m| ^am OmVm h ? AWdm mZ = 78 g mol 1) Ho$ 19 5 g H$mo 500 g Ob | KmobZo na {h m H$ | 1 C H$m AdZ Z XoIm J m & F CH2 COOH H$s {d moOZ m m n[aH${bV H$s{OE & [ {X m J`m h : Ob Ho$ {bE Kf = 1 86 K kg mol 1] 1+1 F CH2 COOH ( moba H$maU Xr{OE (i) (ii) .56/3/1 3 3 : 0 1 M KCl H$m dWZm H$ 0 1 M byH$mog H$s VwbZm | C MVa hmoVm h & bdU { bmZo na m g A{YH$ g VH$ n[aa{jV ahVm h & 18 1 1 37. (a) A solution contains 5 85 g NaCl (Molar mass = 58 5 g mol 1) per litre of solution. It has an osmotic pressure of 4 75 atm at 27 C. Calculate the degree of dissociation of NaCl in this solution. 3 (Given : R = 0 082 L atm K 1 mol 1) (b) State Henry s law. Why is air diluted with helium in the tanks used by scuba divers ? 1+1 OR (a) When 19 5 g of F CH2 COOH (Molar mass = 78 g mol 1) is dissolved in 500 g of water, the depression in freezing point is observed to be 1 C. Calculate the degree of dissociation of F CH2 COOH. 3 Give reasons : (i) 0 1 M KCl has higher boiling point than 0 1 M Glucose. (ii) Meat is preserved for a longer time by salting. 1 1 [Given : Kf for water = 1 86 K kg mol 1] (b) .56/3/1 19 P.T.O.

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