Chemistry 2014 FOREIGN SET (56/2/1)

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1 PDF Compressor Free Version MARKING SCHEME Chemistry 204 FEIGN SET (56/2/) Collectors enhance non-wettability of the mineral/ore particles 2 van der Waals forces 3 Because of high inter-electronic repulsion of non bonding electrons owing to the small bond length / atomic size 4 Coordination isomerism 5 r= or 4r = a 6 2 hydroxybenzaldehyde 7 CH 3 NH 2,because of the electron releasing (+I effect) tendency of methyl group + 8 Amylose and amylopectin 9 m= z I t I=5 A t= 20 x 60s = 200s atomic mass m= x I x t n x F 5. m= x C x 5 A x 200 s m=.825 g (or any other suitable method) 0 Half-life of a reaction is the time in which the concentration of a reactant is reduced to half of its initial concentration. + 4Ag + 8 CN - + 2H 2O + O 2 4 [Ag(CN) 2] OH - 2[Ag(CN) 2] - + Zn [Zn(CN) 4] Ag Or Ag 2S + 4NaCN 2 Na[Ag(CN) 2] + Na 2S 2Na[Ag(CN) 2] + Zn Na 2 [Zn(CN) 4] + 2Ag (balancing of equation is not necessary) 2 Rhombic and Monoclinic Rhombic Sulphur Rhombic sulphur changes to monoclinic sulphur 2 a) High pressure and low temperature b) Because ionization of HSO - 4 is difficult / removal of proton from negatively charged HSO - 4 is difficult. 3 4 Hydridization : sp 3 d 2 shape octahedral IUPAC hexafluoridocobaltate(iii) +

2 5 PDF Compressor CH 3 CH 2- Cl + Free KOH (aq) Version CH 3 CH 2 OH +KCl 6 a) -Bromobutane / CH 3 CH 2 CH 2 CH 2Br Because it is a primary alkyl halide b) Because carbocation formed in S N reaction is sp 2 hybridized and planar. 7 HBr H + + Br - + Or ( where R = -CH3) 8 Br 2 / H 2O or aq. Br 2 LiAlH 4 or NaBH 4 or H 2 / Ni (or any other) (iii) R Cl and anhyd. Al Cl 3 (iv) Acidic or alkaline KMnO 4, K 2Cr 2 O 7 (acidic) 9 Schottky defect, due to similar size of K + and Cl - ion n-type (iii) CO 2 (iv) Ferromagnetic 20 a) The fuel cell runs continuously as long as the reactants are supplied Highly efficient (iii) Pollution free (any two) b) log Kc = ne cell. x4=2 + log Kc = xe cell. 2

3 PDF Compressor Free Version log 0 = xe cell. E 0 cell =. = V [log 0 = ] 2 SO2 Cl2 SO2 + Cl2 At t = 0s 0.4 atm 0 atm 0 atm At t = 00s (0.4 x) atm x atm x atm Pt = 0.4 x + x + x Pt = x 0.7 = x x = 0.3 t t log log.. -. log s - a) p/n or log (x/m)= log k + /n log p b) Dispersed phase = liquid Dispersion medium = Solid c) Because of coagulation of colloidal particles 23 a) oxidation states b) Transition elements Form coloured compounds 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 23 a) Because of stable half filled orbitals (3d 5 ) b) Because Zn has no unpaired electrons in d orbitals. c) Because of the presence of one unpaired electron in Ti 3+ whereas there is no unpaired electron in Sc A = CH 3CN B = CH 3CH 2NH 2 C = CH 3CH 2OH A = CH 3 CONH 2 B = CH 3NH 2 C = CH 3NC 25 Anomers are the isomers which differ only in the configuration of hydroxyl group at C- of glucose Or

4 PDF Compressor and forms Free of glucose Version are called anomers 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 through diet. 26 The drugs which are used to prevent the interaction of histamine with the receptors present in the stomach wall. Eg. Cimetidine / Ranitidine / Dimetapp (or any other) Chloramphenicol (iii) Because it is unstable at cooking temperature 27 Concern towards environment / caring / socially aware / team work. (atleast two values) Polymers which can be degraded by the action of microorganisms. Eg. PHBV, Nylon -2-nylon- 6/ any natural polymer (iii) Homo polymer 28 Raoult s la : state that for a solutio co tai i g olatile co po e ts, the partial vapour pressure of each component is directly proportional to its mole fraction. Ideal solution. + + T b = i K b x Wcacl Mcacl = 3x0.52 K kg mol - x x x kg 28 a) (iii) = 0.69K or C Azeotrope is a liquid mixture which boils at constant temperature with constant composition. Osmotic pressure : is the pressure applied on the solution side to stop the flow of solvent across the semi permeable membrane from lower concentration of the solution to higher concentration. Colligative properties : are the properties of solution which depend upon the no of moles of solute or concentration of solute and not on the nature of solute. b) M = = x V L V. x (B Solute) M = x.02 M =.02M 29 a) Because Bi is more stable in +3 oxidation state. 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 H 2(g) which prevents the oxidation of Fe +2 to Fe +3 / HCl is only a mild oxidising agent x3=3 4

5 PDF Compressor Free Version a) + 29 a) Polymeric b) Because of the presence of two unpaired electrons. Because of high ionization enthalpy of He. (iii) Because of the presence of two P-H bonds in H 3PO 2 whereas in H 3PO 3 one P-H bond is present. 30 a) CH 3-CHO CH 3MgBr CH 3CH(CH 3)- OMgBr H 3O + CH 3CH(OH)- CH 3 CH 3CHO Zn-Hg CH 3-CH 3 Conc HCl (iii) C 6H 5CHO + CH 3-CHO dil NaOH C 6H 5CH(OH) CH 2CHO (Award full marks even if only products are given) b) Add NaHCO 3, benzoic acid will give brisk effervescence whereas ethyl benzoate will not give this test. (or any other test) ii Add tolle s reage t, propa al ill gi e sil er irror hereas Buta -2-one will not give this test. (or any other test) 5

6 PDF Compressor Free Version 30 a) Because the positve charge on carbonyl carbon of CH 3 CHO decreases to a lesser extent due to one electron releasing (+I effect) CH 3 group as compared to CH 3 COCH 3 (two electron releasing CH 3 groups) and hence more reactive. because one of the NH 2 is involved in resonance with carbonyl group and hence acquires positive charge. (b) (iii) (or any other suitable reaction) Sr. Name & Address Sr. Name & Address No. No. Dr. (Mrs.) Sangeeta Bhatia 9 Sh. Partha Sarathi Sarkar 2 Dr. K.N. Uppadhya 0 Mr. K.M. Abdul Raheem 3 Prof. R.D. Shukla Mr. Akileswar Mishra 4 Sh. S.K. Munjal 2 Sh. Maya George 5 Sh. Rakesh Dhawan 3 Sh. Virendra Singh Phogat 6 Sh. D.A. Mishra 4 Dr. (Mrs.) Sunita Ramrakhiani 7 Sh. Deshbir Singh 5 Ms. Garima Bhutani 8 Ms. Neeru Sofat 6