FIITJEE CHEMISTRY (CBSE) CLASS 12 SOLUTION

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1 FIITJEE EMISTRY (BSE) LASS 1 SLUTIN 1. P4 3Na 3 P3 3Na P. -hydroxy 5-methyl hex-enamide 3. Physiosorption is reversible in nature while chemisorptions is irreversible in nature. 4. Because of intramolecular hydrogen bonding. 5. l 6. (a) Nal (b) (a) R 65 Fel 3 Fe 6 5 3l 3 Pl No Reaction (b) Me Na 3 + M.E. Na 3 = Me l 1 1 w V 106 / 84 /1 10 w 1 w w = 0.56 gm 1 w = 0.44 gm n solving we get V = 15 ml FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

2 8. (a) S S (b) P P 9. A rechargeable cell that converts chemical energy into chemical energy by reversible chemical reaction. hemical reaction Pb 4 S e PbS 4 4 Pb S PbS e (a) Potassium tetra iodido mercurate (II) (b) dibromido bis-(ethane 1, diammine) cobalt (IV) sulphate. 11. (a) (b) (i) I 3 I45 As As (ii) (a) p = 14 log 14 log 14 log log Ksp u u 10 u e u Ecell Ecell log10 u FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

3 E 0.34 log 10 Ecell log = Volt cell (b) w i t E u e u 19.3 t t = 1000 seconds 13. (a) Galena PbS (b) Powdered ore oncentration Forath floatation ore rich in PbS smelting Roasting ore rich in PbS 4, PbS Pure metal Electrolytic refining Pb Metal + Au, Sn Desilverisation Impure metal Liquation Pb + Sn, Ag, Au 14. (a) Lyophillic colloids have strong affinity for dispersion medium while Lyophobic colloids do not have strong affinity for dispersion medium. (b) The phenomenon of change of colloidal state to suspended state is known as coagulation whereas process in which dispersion media break up certain substances into colloidal state is known as peptisation. (c) omogenous catalysis Reactants and catalyst are in same physical state S liquid 5 In eterogeneous catalysis reactant and catalyst are in different physical state Fe N 3 N 3 g g S R FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

4 (a) S S S 3S 3 S S S S S 7 4 (b) 4 S S u S4 us 4 S 15. K.303 log a 10 t 40a a 100 K.303 log 100a a log log 0 60 t 5 t = 54.5 minutes 16. (a) I > II > III (b) III (c) III 17. (a) Froath floatation: It is used for concentration of sulphide ores. (b) Mond s process: It is also known as carbonyl process in this process Nickel oxide convert into nickle 330to350 K Ni 4 Ni K Ni Ni 4 4 (c) hromato graphy: It is a technique for the separation of a mixture by passing it in solution R suspension through a medium in which the component more at different rate. 18. (a) 3 MgBr Mg Br - + FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

5 (b) N NaN + N l 3 P 0 l All 3 / Anhydol 19. (a) Nylon 6 is only made form on kind of monomer called capolactum: N n N n Nylon-6 (b) The polyester is polyethylene terypthalate (Dacron) is a condensation co-polymer formed from ethylene glycol (1, ethanediol) and terypthalic acid. + (c) + Bakelite 0. (a) ardy Schulze rule: Greater the valiancy of the oppositely charge ion of the electrolyte being added the more is the coagulation. (b) Gold number: It is defined as the minimum amount of protective colloidal in milligrams which prevents a colour change from red to violet. (c) Micelle: An aggregate of molecules in a colloidal solution. Such on those formed by detergent. FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

6 1. (i) Aqua regia produced [l] which oxidized Ag, Au and u. (ii) Due to presence of vacant d orbital in P and S they have more electron gain enthalpy than N and oxygen. (iii) N 5 on hydrolysis given N 3 while N 3 form N. The N 3 is more acidic because oxidation number of N is +5 while in N N of is +3.. (a) Due to o and p directing nature of N so Ist it protect with actyl chloride or actic anhydride then allow to hydrolysis this group replaced. (b) Due to resonance in aniline it is less basic than N 3. (c) Pentactyl glucose does not react with hydroxyl amine because does not contain aldehyde group(ring structure). 3. (a) Potassium bromate and potassium iodate. (b) Wheat starch (c) helix and sheet structure (d) vitamin B 1 and vitamin B 4. (a) (i) Because of unpaired e and d d transition. (ii) Because of very low MP due to this they formed vapour easily. (iii) Due to formation of the complex salt. (b) Similarity : Both show +3 oxidation state. Difference: Lanthanids have less tendency to form complex while actinide have high tendency to form complex. R (a) 4Fer 4 8Na 3 7 8Na r4 Fe3 (b) (i) Nar Na r Na 4 7 Na r Kl K r Nal (ii) (a) Molar of solorts = = Tf Tf Tf = T 3.03 f Mn S Mn S Mn I Mn I (b) smotic pressure : The external pressure required to prevent the osmosis through semi permeable membrane from high concentration to low concentration. (c) Molality: Number of mole per kg of solvent. FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

7 R ' (a) Tf kf m i = x i x = x i i = 3 i1 n 1 31 l so the formula is [Pt(N 3 ) 4 l ]l n 1 n 1 = n = 3 (b) Non ideal solution: A solution which do not obey Roult s law known as non ideal solution. When the total pressure of the solution is less than the sum of the partial pressure of solute and partial pressure of solvent. 0 0 Ptotal PA XA PB XB Example: l 3 + l (a) (i) Pb Mg Br/ Pb (ii) + (iii) N Br / N (b) (i) Aniline gives positive test for coupling reaction. Aniline reacts with benzene diazonium chloride in basic medium to give p-aminoazobenzene which is yellow is colour. Ethyl amine does not give coupling reaction N + N Nl + NaN + l + (ii) acetaldehyde gives silver mirror with Tollen s reagent Ag N N Ag 3N Acetone does not give this test FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

8 R (a) (i) Reimer Tiemann s reaction: It is the reaction of phenol an alkali at 60 o. a group is introduced in the ortho position of the benzene ring, leading to the formation of -hydroxy benzaldehyde. l 3 /aq. Na Na+ l (i) Na (ii) + Salicyladehyde (ii) Stephen s reduction: Nitriles are reduced to corresponding imine with stannous chloride in the presence of l, which on hydrolysis give aldehyde. 3 R N Snl l R N R (b) (i) Benzonitrile to acetophenone N Br / N (iii) Phenol to ortho and para salicylic acid (i) l 3 /K (ii) xidation + FIITJEE Ltd. Kanpur entre 16/116 Karmin Arcade (opp to IT) ivil line, Kanpur. Mob ;

INDIAN SCHOOL MUSCAT THIRD PRELIMINARY EXAMINATION CHEMISTRY ANSWER KEY

Roll Number Code Number 4 / INDIAN SCHOOL MUSCAT THIRD PRELIMINARY EXAMINATION CHEMISTRY ANSWER KEY CLASS: XII Sub. Code: 04 08.0.018 1. P type semiconductor 1. 1. (C H 5 ) N > (C H 5 ) NH > C H 5 NH >