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MODERN VIDYA NIKETAN SR. SEC. SCHOOL CLASS : XII SUBJECT : CHEMISTRY SOLUTION 1. In Frenkel defect, a cation is missing from its lattice site and occupies interstitial side. Eg. Nacl. Electrical conductance increases due to this defect. 2. 1 x KP n m log x 1 logK logP m n So the slope indicates 1 where n is order of reaction. n 3. CH3 | CH3 C Cl will react fastest as it will form most stable carbocation. | CH3 4. At temperature above 983K, coke is better reducing agent. However below this temperature, carbon monoxide is a better reducing agent than coke. 5. Ethylcyclohexane carboxylate 6. CH3CH2NH2 will give carbylamine reaction and CH3CH2 2 NH will not CH3CH2 NH2 CHCl3 KOH CH3 CH2 N C 3KCl H2O 7. Essential amino acids are those which cannot be synthesized in body e.g. Lysine, Leucine, valine etc 8. In R3P = O there is p d bonding which is not possible in R3N O 9. Henry’s law PA k Hx A Its application is in dissolution of CO2 in cold drinks. 10. KA e Ea RT slope l n K = l n A Ea nK RT A slope of 11. Ea R l nK Vs 1 graph will be equal to Ea . T nA R 420 425K Al 2O3 2H2O 2NaOH 2NaAl O2 3H2O Sodium meta aluminate (water soluble) Page 1 NaAl O2 2H2O Al OH3 NaOH 2Al OH3 Al 2O3 3H2O 12. (i) Because sulphur cannot undergo sp3d2 hydridisation in presence of H atoms. (ii) As we move down the group in hydrides of group 15, bond angle decreases due to decrease in bond pair-bond pair repulsion. 13. (i) O OH || | C6H5 CH CH C H | CH3 ONa OH (ii) 14. (i) A low concentration of H+ ion pH 4 5 helps in removal of H2O, but further increase in H+ concentration may protonate the nucleophile. (ii) Presence of anhd. AlCl3, NH2 acts as a Lewis base. NO2 15. conc.HNO3 conc.H2SO4 (i) NH2 Sn, HCl N C CHCl3, KOH (ii) 16. C6H5MgBr H2 O,H CH3 C N CH3 C NMgBr CH3 C O | | C6H5 C6H5 H OH C CHOH CHOH O CHOH CH CH2OH Glucose does not respond to 2, 4-DNP test Page 2 17. (i) Globular protein (ii) Fibrous protein (1) Sherical in shape (1) Linear in shape (2) Part of blood and egg yalk (2) Part of dead tissues like hair and nails Nucleoside – has nitrogenous base and pentose sugar Nucleotide – has nitrogenous base, pentose sugar and phosphate group OR 18. (1) As source of energy (2) As structural material (3) Reserve food (4) Maintenance and body growth Calcium bicarbonate makes water hard. Soap (RCOONa) will react with the salt to form corresponding calcium salt which will be precipitated and wasted 3RCOONa Ca HCO3 2 RCOO 2 Ca 2NaHCO3 The synthetic detergents do not react with Ca HCO3 2 and therefore can be used without being precipitated 19. Atomic mass, M = 60g/mil, density, Z l = 6.23 g/cm3 edge length a = 400pm = 4×10—8cm l a3 NA M 6.23 4 108 6.022 1023 3 60 = 4 four atoms per unit cell are present in FCC lattice So, r 20. (a) a 2 2 400 141.44pm 2 1.414 Oxidation state of Pt x 4 1 2 x 2 El . Confign of Pt (II) Xe 5d 6s 6P In strong field of CN—, it rearranges as Xe dsp2 So shape of Pt CN 4 2 hybridisation is square planar. Page 3 FeSO4 . NH4 2 SO4 6H2O (Mohis salt) gives free Fe2 ions in solution but CuSO4 and NH3 react as (b) CuSO4 4NH3 Cu NH3 4 SO4 As there is no free Cu2 ion 21. 22. 23. 3 3 WBRT 1.26 10 10 g 0.0821 300 MB V 2.57 103 0.2 K 2.303 Pi log t 2Pi Pt K360 2.303 35 log 2.17 103 s 1 360 70 54 K720 2.303 35 log 2.24 103 S1 720 70 63 (i) The positively charged sol particles of ferric hydroxide get their charge neutralized by interacting with negative chloride ions Cl . As a result, they get coagulated. (ii) Smoke and dust in factories have dispersions of electrically charged particles in air. When these are passed between two electrodes at a potential difference of 50,000V. these particles are discharged and precipitated. 24. (i) Hofmann bromamide reaction O || Heat CH3 CH2 C NH2 Br2 4KOH CH3CH2NH2 2KBr K2CO3 2H2O Pr opanamide (ii) Hydroboration oxidation H2O2 / OH 3CH3 CH CH2 BH3 CH3CH2CH2 B 3CH3CH2CH2OH H3BO3 H2O Propane (iii) Sandmeyer reaction N NCl Cl CuCl/HCl N2 Benzene diazonium Chloride Page 4 Cl Cl OH Cl OH Cl OH N N N slow step OH NO2 25. O (a) Cl OH O O O O OH fast step Cl N O O N O O O C N NHCONH2 H (b) Br Br2 UV light (c) 26. H2C C CH CH3 | | A CH3 CH3 Cl H | | B CH3 C C CH3 | | CH3 CH3 C Cl CH2 CH CH CH3 | | CH3 CH3 D CH3 C C CH3 | | CH3 CH3 O || E CH3 C CH3 F O C CH CH3 | | CH3 CH3 O || G H C H 27. (a) H2O H2N CH2 COOH H2N CH2 5 COOH NH2 CH2 CO NH CH2 5 COOH NH CH CO NH CH 2 2 5 CO n Page 5 (b) Vulcanization is addition of a small amount of sulphur to molten rubber at temperature ranging between 373 to 415 K. Vulcanized rubber is more elastic, less water absorbing and more resistant to oxidation and towards organic solvents. 28. (a) Fuel cells convert the energy of combustion of certain fuels into electrical energy without the use of a heat engine e.g. H2 O2 fuel cell. Reactions (b) at anode : 2H2 g 4OH aq. 4H2O l 4e at cathode : O2 g 2H2O l 4e 40H aq. overall : 2H2 g O2 g 2H2O l 0 0 0 Ecell Ecathode Eanode = 0.80 0.34 = 0.46V The reaction will be Cu S 2Ag aq. Cu2 aq. 2Ag S Ecell E 0 cell Cu2 0.0591 log10 2 n Ag = 0.46 0.0591 4 log10 2 0.12 0.46 .0591 2.6020 2 0.353V OR (a) Discharging Pb S SO24 aq. PbSO4 S 2e oxidation PbO2 S SO24 aq. 4H aq. 2e PbSO4 S 2H2O l Reducation Pb S PbO2 S 4H aq. 2SO24 aq. 2PbSO4 S 2H2O l Page 6 During Charging PbSO4 S 2e Pb S SO24 aqReduction PbSO4 S 2H2O l Pb S PbO2 S 4H aq. 2SO24 aq. (b) 1 I aq. Fe3 aq. Fe2 aq. I2 g 2 0 Ecell 0.77 0.54 0.23V 29. (a) 2KMnO4 3H2SO4 5H2S K2SO4 2MnSO4 8H2O 5S (b) Ce has electronic configuration Xe 4f1 5d1 6s2. In Ce (IV) it acquires noble gas configuration. (c) In Fe3+, the electronic configuration is Ar3d5 which is more stable than Fe2+ with electronic configuration Ar 3d 6 In Mn3 , the electronic configuration is Ar 3d which is less stable than Mn2 with configuration Ar 3d 4 30. (d) Cu2 has very high solvation energy which easily compensates 2nd ionization enthalpy of copper. (e) It is due to lanthanoid contraction (a) 5 4Zn 10HNO3 dil 4Zn NO3 2 H2O N2O nitrousoxide F F Br F F F (b) square pyramidal (c) MI MBr MCl MF It is due to increase in electronegativity difference (d) It is due to highest E0value of F2 among halogens. (e) Chlorine reacts with water to evolve nascent oxygen which brings about both oxidation and bleaching. As oxidizing agent Cl 2 H2O 2HCl O SO2 H2O O 2HCl O Cl 2 SO2 2H2O 2HCl H2SO4 Page 7 As bleaching agent Cl 2 2H2O 2HCl O colourless product Coloured substance O Page 8