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Pre Council EPmination - 2019 M.M. 70 ClassXII Paper- J Cbet11istry (Theory) Time :-3hrs AL-70 .,.d llowedadditiona/J51t1inutesforonlyreadingthepaper Can:ll aIe are a . tbe tim They must not start writing during e. , PART-1 (20 marks) Answer all questions Question-1 (a)Fill in the blanks by choosiug appropriate word from those given in the brackets: \ (Nature,number,lime,tetragonal,unity,trihydric,decreases in temperatur~,does not change,di yaric,zero,sweets,four,anode,methyl cyanide,cathode,nitrous,acid, solutions,slow,overall,order,molecularity) (i)The crystal system in which all three axes are at right angles to each other but only two axes are equal is known as--------- . (ii)ln an electrochemical-cell, negative terminal is------ and positive terminal is----------- l (iii)---ofa.reaction is sum of number ofmolecules of reactant taking part in---------Step of reaction. (iv)Extent of physisorption of gas increases with-------(b) Complete the following choosing correct alternative from given choices: l .The stereoisomers which are related to each other as non superimposable mirror images a. geometricaJ isomers c. Tautomers d. Diastereomers ....-b'Enantiomers 2.0ctahedral compl~xes have hybridisation oftype a.sp3 c.sp2d /4sp3d2 d.dsp2 3.Molecular mass ofNa S0 2 4 as determined by use of colligative property a. Equal to nonnal molecular weight b. half of nonnal value c. Double the normal value /4. One-third of normal value (1) +2 (Paper-1) Chemistry (Theory) (1-6) 70 .-- 4 . The purple colour ofKMnO4 is due to 4 c. f.f transitions d-d transitions d. d-f transitions b . charge transfer f ethylene 1'acetaldehyde ' t , ' 5. The alcohol that produces turbidity immediately with ZnCh/conc.HCI at room temp. Is: a. 1-hydroxybutane c. 2-hydroxy-2-methylbutane ~ b. 2-hydroxybutane d. t -hydroxy-2-methylpropane c)Answer tbe following questions: 1 1. The conductivity of 0 .8M electrolyte is 2x102n 1cm ,Calculate its,'im value. . ' 2. Why reactions with Grignard' s reagent should be strictly carried out under anhydrous conditions? 3 . Chlorobenzene on niration yields both o and p-nitrochlorobenzene but nitrobenzene on Chlorination yields m-chloronitrobenzene. Why? 4. ldentify t~e.order of reactions of each of foll . Reactions: a. mol L 1s 1 b. mor 1 Ls 1 5. \Vhy N02 dimerises and exist as N204 ? l (d) Match the following: - - - ~ c. 2 . ethanol e.. b. Zwitter ions 4 3. acetone d c.poisonous \ i::, d. lodofo'(' ..v\ _3, 4. glycine a. fermentation !l. 1. methanol PART - 11(50 marks) SECTION-A Followlng quesfions from 2-8 carries 2 marks each Question-2 A solution contains 0.520g glucose dissolved in 80.2g water. Calculte (i) Boiling point of solution (ii) Freezing point of solution[K,=1 .861</molal, Kb=0.52K/molal] OR (i)Give reason why finely dividcd substance is more effective as adsorbent. (2) +2 (Paper-!) Chemistry (Theory) (1-6) 70 --(ii)What is hybridisation of carbon atom in diamond? What is the number.of closest number of neighbours around each carbon atom? HoW are they oriented? How are the carbon atoms held together? Question-3 (i) How many formula units of sodium chloride are present in a unit cell of sodium chloride? (ii) To what type of cubic system does the cell belongs? - Question-4 (i) Why d-block elements and their compounds are coloured? (ii) Why pentavalent bismuth is a good oxidizing agent? OR (i) What is lanthanoid contraction?Give example. (i i) What are consequences of Ianthanoid contraction? Question-5 Calcu late the electrode potential of half cell at 298K 2 M/1 Fe Fe + (0. 1 E F/+/Fe= -0.44V Q uc~/ iela-6 WhM ,~ :hfference between order of reaction f1nd its molecularity?Explain your answer properly giving suitable examples wherever required . Question-7 ."or the reaction : 2H2 + 2NO-- 2H2O + N2. the following rate data was obtained :;.No [NO]mol L 1 1 0.40 [H2]mol L - 1 . Rate mol L 1 sec 0.40 4 .6XIO--' . - 0 .80 0.40 18.4X 1O--' ' 0.40 0.80 9 .2XIO--' . : "'~alculate the followmg (i) The overall order of reaction (ii) The rate law (iii) Tue value of rate constant Question-8 Explain homogenous and heterogenous catalysis .Give examples to support your answer. (3) +2 (Paper-!) Chemistry (Theory) (1 -6) 70 \ ~e SECTION-B / Each question from 9-15 carrlea 3 111arks each / 1 Questlon-9 (a) Write thc formula of following compaunds: (i) Potassium trioxalatoaluminatc(III) ( ii) Hexaaquairon(II)sulphate (b) Name the types of isomcrism shown by following pairs of compounds: (i) [Cu(NH3)4)[PtCl4] and [Pt(NH3)4][CuCl4] (ii) [Co(Pn)2Cht and [Co(tn)Ctif OR Find the coordination complex ion [Co(NH 3) 6] 3+ (i) Give IUPAC name of compound (ii) What is the oxidation number of cobalt in complex? (iii) State the type ofhybridisation in coordination complex ion. (iv) ~ Give the structure of complex ion. Qu, .t::>n- 10 (iJ \ _ ) f1 '!J/d,,__ What are types ofhybridisation of iodine interhalogen compounds IF3, IFs, I respectively? (ii) Draw the structures ofxenin hexafluoride(XeF6 ) molecule and state the hybridisation of central atom. Question-11 Draw the structures ofthe following: (ii) NH3 {iv) PCh (v) H3P03 (i} What is Holme's signal? (ii} What happcns when D-glucose is treated with following reagents: a. m b. Bromine water c. HN03 Question-12 Write equations for tbe extraction of potassium permanganate and potassium dichromate from their ores. (4) +2 (Paper-1) Chemistry (Theory) (1-6) Question-13 Give following reactions: (i) Aldol condensation (ii) Crossed aldol condensation (iii) HVZ reaction Question-14 Explain the following: (i) Oxidation states of group 17 elements (ii) Anomalous behaviour of nitrogen. (iii) Aniline is less basic than methylami ... Question-15 Give reaction ofbenzene with: (i) Conc.HN03 (ii) conc.H2 S04 (iii)chlorine and bromine SECTION-C Eacb questions 16-18 carry 5 marks cach Question-16 (i)C o:nplete the follow ing reaction : \ (a) C 6HsNH2 +CH3COCl+NaOH--- (b) C6HsN02 + Sn/HCI --- (c) C 6 H 5 CHO +conc.NaOH--- (d) C 6 H 5 0H +conc. HN03--- (ii) Explain whyn dimethyl cadmium is preferably used in preparation of ketones from acid chlorides . In what respect it is better than RMgX? OR (i)How will you distinguish between : (a) Formic acid and acetic acid - ,\, (b)Ethanol and phenol (ii) Name two fat s o ~ vitamins and mention their deficiency disease. Question-17 r (i) Name the monomers of cellulose,Nylon-66 (ii) Give one important use of PVC aod T~on (5) +2 (Paper-1) Chemistry (Theory) (1-6) 70 What is monomer of (--CH2-Ctb---o-CHr--CHi---O--)n (iii) OR (i )Name the hexadentate Ugand and writc the fonnula of its _complex with Co(II~. Draw jts structure. (ii)Draw structures of: Meta phosphoric acid 8 b. Ortho phosphoric acid c. Pyrophosphoric acid d. Hypophosphoric acid i e. Phosphoric acid r Question-18 Give following reactions: (i) Rosemund's reduction (ii) Benzoin condensation (iii) ~itration reaction ofbenzene (iv) Diazotisation reaction I' .. -; \ Hoffmann degradation OR (i) Identify X,Y,Z in following reactjon C2HsCOQH +PCls-- X + NH3- Y +Br2/KOH--- z (ii) Explain why p-nitrobenzoic acid is stronger than benzoic acid? (iii) How will you account for the acidic nature of carboxylic acids? (6) +2 (Paper-1) Chemistry (Theory) (1-6) 70
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