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THE INDIAN PUBLIC SCHOOL, DEHRADUN CHEMISTRY PAPER 1(THEORY) [ PRE-BOARD-1] Date -14/12/16 (Three Hours) KSB[12] (Candidates are allowed additional 15 minutes for only reading the paper. They must NOT start writing during this time) -------------------------------------------------------------------------------------------------------------------------Answer all questions in Part I and six questions from Part II, choosing two questions from Section A, two from Section B and two from Section C. All working, including rough work, should be done on the same sheet as, and adjacent to, the rest of the answer. The intended marks for questions or parts of questions are given in brackets [ ]. Balanced equations must be given wherever possible and diagrams where they are helpful. When solving numerical problems, all essential working must be shown. In working out problems use the following data: Gas Constant R = 1.987 cal 1 l atm = 1 dm 3 deg 1 mol 1 = 8.314 J K 1 mol 1 = 0.0821 dm 3 atm K 1 mol 1 atm = 101.3 J. 1 Farday = 96500 Coulombs PART I Answer all questionss Question1 (a) Fill in the blanks with appropriate words given below : (Isopropane, oxidising, molar concentration, Above, increases, decreases, blue reducing, monodentate, polyamide, bidentate, HCl, NaCl, concentrated H2SO4,Ionic concentration, concentration) (i) Law of mass action state that the rate at which a substance reaction proportional to its -------(ii) Oxalate ion is a----------- ligand while NH3 is a ---------- ligand (iii) an aqueous solution of sugar is boils hundred 1000C and freezes ------00C (iV) MnO2 when heated with----------- and--------- liberates chlorine (v) the monomer of natural rubber is-----(B) Complete the following statements by selecting the correct alternative from the choices given (a) Manufacture of NH3 by Haber,s process is favoured by : (i) High temperature, low pressure (ii) low temperature, high pressure (iii) high temperature and pressure (iv) low temperature and pressure (b) Sulphur can be extracted from deposits in Earth crust by (i) Froth flotation process (ii) Frasch process (iii) frankel process (iv) friedel craft process (c) Formation Of cyanohydrin with an aldehyde is an example of (i) electrophilic substitution (ii) nucleophilic substitution (iii) nucleophilic addition (iv)electrophilic addition (d) Enzymes are (i)Carbohydrates (iii) Nucleic acid (ii) vitamin (iv) Biocatalyst (e) Of the following compounds, the one which is a Lewis acid is (i) PCl3 (ii) AlCl3 (c) NCl3 (d) AsCl3 (C) Answers the following question: (i) What is the pH of a solution shows hydroxyl ion concentration is 10 -2 M (ii) Define heterogeneous catalyst with examples (iii) What is meant by coordination number? (iv) Name the bases present in DNA (v) Give balanced chemical equation for laboratory preparation of chlorine gas (D) Match the following s.no s.no. N M . A P Cryoscopic Electrolysis B Q crystal field theory depression in freezing point C R Faraday's law urea D S solubility product salting of soap E T Wohler coordination compounds PART II Answer six questions choosing two from Section A, two from Section B and two from Section C. SECTION A Answer any two questions Questions-2 [A] (i) A 5% solution of sucrose( molecular weight 342) is isotonic with 0.877 % solution of Urea.Find molecular weight of urea . (ii) When 1gm Non-volatile substance was dissolved in 10 gram benzene, elevation in boiling point was found 1 0C. calculate the molecular weight of dissolved substance (kb for benzene is 2.530K kg/mol (iii) Write the difference between ideal and non ideal solution also draw graphs for nonideal solution [B] (i) State the Faraday's law of electrolysis. (ii) A first order reaction has a specific Reaction rate of 2.31X10 -3 s-1 calculate the Half Life of the reaction. (iii) Write difference between frenkel and schottky defects. Question-3 [A] Niobium Crystallize in body centred cubic structure. if its density is 8.55 gm/cm3 calculate the atomic radius of Niobium. (atomic mass of niobium =93u Na=6.02X1023 mol-1) (ii) For the following cell : Al / Al 3+(0.01M) // Fe2+(0.02M) / Fe Given E0Al 3+ / Al = -1.66V E 0 Fe 2+ / Fe = -0.44V (a) Calculate the emf of the cell (b) write the cell reaction (c) Cell reaction is spontaneous or not . (i) (i) Ionic product of water at 310K is 2.7x10 -14 . What is the PH of Neutral water at this temperature . (ii) A saturated solution of Ag 2SO4 has solubility is 2.5x10-2M. calculate the solubility product of Ag2SO4. (iii) PCl5, PCl3 and Cl2 are at equilibrium at 500K and having concentration 1.59M PCl3 1.59M Cl2 and 1.41M PCl5 , calculate the Kc for this reaction . PCl5 PCl3 + Cl2 [B] Question-4 [A] (i) State Le-Chatelier principle . Discuss its application in the formation of NH 3 by Haber,S process. (ii) Consider the following data for the reaction A + B Product Experiment No 1 2 3 [A] mol/lit 0.10M 0.20M 0.30M [B] mol/lit 1.0M 2.0M 3.0M Rate mol/sec 2.1x10-3 8.4x10-3 8.4x10-3 Determine the order of reaction with respect to A and with respect to B and the overall order of reaction . (iii) Explain the buffer action of an acidic buffer . [B] (i) How much charge is required for each of the following reduction process (a) 1 mole of Al3+ to Al (b) 1 mole MnO4- to Mn2+ (c) 1 mole Mg2+ to Mg (ii) An Arrhenius reaction for a certain reaction , The value of A and E a are 4x1013sec-1 and 98.6KJmol-1 respectively . If the reaction is first order , at What temperature will its half life period be 10minute? (iii) In a first order reaction , 10% of the reactant is consumed in 25minute .Calculate: (a) The half life period of the reaction (b) The time required for the completion of 87.5% of the reaction. SECTION B Answer any two questions Question-5 [A] (i) Write the IUPAC name of K[PtCl 3(NH3)] and K4[Fe(CN)6] (ii) Explain the geometry , magnetic nature and hybridization of central metal atom in [Fe(CN)6]3- using VBT. (iii) Write any two important use of coordination compound . [B] (i) Complete the balance the following equation (a) NaOH + NaOCl + ------- + -----(b) F2 + --------- HF + O3 (c) KMnO4 + FeSO4 + ------- K2SO4 + ------- + --------- + --------- + H2O (ii) Name all the element of group 17 Th . Out of the elements named by you which element has the (a) Highest ionization potential (b) Highest electron affinity (c) Radioactive nature . Question-6 [A] [B] (i) Define Lanthanides contraction (ii) Write the preparation methods of Sulphuric acid by contact process (iii) Write any three use of Hydrochloric acid . (i) What happen when SO2 react with Cl2 in presence of sunlight . (ii) Define inter-halogen compound . Also draw the structure of following compound , write the hybridization sate . (a) I 3- (b) ClF3 Question-7 [A] [B] (i) The Boiling point of HF is greater than HCl Why? (ii) Fe3+ Is more paramagnetic than Fe2+ ion Why ? (iii) Define ambient ligand with example . (i) Iron can be extracted from ore of haematite . Describe the steps and equations involved in the extraction of metal from this ore . (ii) What is flux ? Give an example , writing the relevant equation . (iii) H2O2 acts as an oxidizing and a reducing agent Give example . SECTION C Answer any two questions Question-8 [A] How will you prepare : (i) Nitrobenzene from Benzene (ii) Propanol-1 from propene (iii) Chloroform from acetone (iv) Benzene to TNP. [B] How will you difference between : (i) Aniline and ethyl amide (ii) Benzaldehyde and Acetaldehyde (iii) Glucose and fructose Question-9 [A] (i) Name the monomer and one use of following (a) Nylon-6 (b) Teflon (c) Bakelite (ii) Write three difference between DNA and RNA . [B] (i) Give an example for each of the following named reaction (a) Aldol condensation (b) Reimer-Tiemann reaction (c) Wolf kishner reaction (ii) What is Vitamins ? Deficiency of what vitamins causes (a) Night blindness (b) Scurvy Question-10 [A] (i) In phenol and phenoxide ion which is more acidic and Why? (ii) Write the mechanism of formation of ether from ethanol [B] (i) What is hinsbergs reagent ? Distinguish between 1 0 ,20 and 30 amine by Hinsbergs reagents . (ii) An organic compound [A] has characteristic order on treatment with NaOH its forms Two compound [B] and [c].Compound has molecular formula C 7H8O which on oxidation give back [a] . The compound [C] is a sodium salt of an acid . When [C] is treated with soda lime its yields an aromatic hydrocarbons [D] . Deduce the structure and chemical reaction for [A] , [B] , [C] and [D] . THE INDIAN PUBLIC SCHOOL, DEHRADUN PAPER 1(THEORY) [ PRE-BOARD-2] Date -01/02/17 (Three Hours) KSB[12] (Candidates are allowed additional 15 minutes for only reading the paper. They must NOT start writing during this time) -------------------------------------------------------------------------------------------------------------------------Answer all questions in Part I and six questions from Part II, choosing two questions from Section A, two from Section B and two from Section C. All working, including rough work, should be done on the same sheet as, and adjacent to, the rest of the answer. The intended marks for questions or parts of questions are given in brackets [ ]. Balanced equations must be given wherever possible and diagrams where they are helpful. When solving numerical problems, all essential working must be shown. In working out problems use the following data: Gas Constant R = 1.987 cal 1 l atm = 1 dm 3 deg 1 mol 1 = 8.314 J K 1 mol 1 = 0.0821 dm 3 atm K 1 mol 1 atm = 101.3 J. 1 Farday = 96500 Coulombs PART I Answer all questions Question1 (a) Fill in the blanks with appropriate words given below : ( decreases, aldol reaction, two degree , cannizaro reaction , one degree, NH3, ketone, NH- , increases , Formaldehyde, , three degree, remain same, ) (i) Carbylamines test is given by-------------- amine. (ii) Formaldehyde undergo ------------- reaction in presence of dil.NaOH (iii) Conjugate acid of NH2- ion is -----------(iv) when a solute is dissolved in a solvent , the vapour pressure of the solution ---------(v) Ammonia when heated with --------- yield urotropine. (B) Complete the following statements by selecting the correct alternative from the choices given (a)Magnesium displaces hydrogen from dilute acid solution because: (i) The oxidation potential of magnesium is less than that of hydrogen. (ii) The reduction potential of magnesium is less than that of hydrogen. (iii) Both magnesium and hydrogen have same oxidation potential. (iv) Both magnesium and hydrogen have same reduction potential (b) Out of the following solution which is highest boiling point (i) 0.1M NaCl (ii) 0.1M BaCl2 (iii) 0.1M KNO3 (iv) 0.1M K4[Fe(CN)6] (c)75% of a first order reaction complete in 32 minutes . When was 50% of the reaction completed ? (i) 24minute (ii) 16 minute (iii) 8 minute (iv) 4 minute (d)Among the following compounds, the one showing geometric isomerism is (i) [Cu(NH3)4]2+ (ii) [Pt(NH3)2Cl2] (iii) [FeNO(CN)5]3(e) An example of colligative properties is: (i) Boiling point (ii) Freezing point (iii) Vapour pressure (iv) [Co(en)3]3+ (iv) Osmotic pressure (C) Answers the following question: (i) Calculate the number of coulombs required to deposite 20.25 g of aluminium (at. mass = 27) from a solution containing Al3+. (ii) What is the difference between thermoplastic and thermosetting plastic. (iii) What is the vant,hoff factors. Under what condition vant hoff factor is grater or less then to 1. (iv) Define ferromagnetism (v) Write the of element in 17th group which is maximum ionization potential (D)Match the following: s.no. (a) (b) (c) CHCl3 + NaOH Proteins Carbohydrate [M] S.no. (p) (q) (r) Fluorine Starch Ammonia [N] (d) Lewis base (s) Peptide linkage (e) KHF2 (t) Isocyanide test PART II Answer six questions choosing two from Section A, two from Section B and two from Section C. SECTION A Answer any two questions Questions-2 [A] (i) Calculate the freezing point of solution when 1.9 g of ( = ) was dissolved in 50g of water, assuming undergoes complete ionization. ( = . ). (ii) Too 500Cm 3 of water , 3x10-3kg of acetic acid is added . if 23% of acetic acid is dissociated , what will be the depression in freezing point ? K f and density of water are 1.86K kg mol -1 and 0.997g cm-3 respectively (iii) Equal weight of two substances X and Y are dissolve in equal volume of water . The osmotic pressure of solution containing Y is five times the osmotic pressure of the solution containing X. What is the molecular weight of X if that of Y is 60? [B] (i) A reaction is of second order with respect to a reactant . How will the rate of reaction be affected if the concentration of this reactant is (p) Double (q) Reduced to half (ii) Consider the reaction A + B P , gave the following data at 25 0C Exp. [A] [B] d[product]/dt 1 1.0 0.15 4.20x10-6 2 2.0 0.15 8.40x10-6 3 1.0 0.20 5.60x10-6 Find (a) the order of reaction with respect to A (b) the order of reaction with respect to B (c) The rate law (iii) In general , It is observed that the rate of a chemical reaction double with every 10 0C rise in temperature . If this generalization hold for a reaction in the temperature range 298K to 308K, What would be the value of activation energy for this reaction ? (R = 8.314JK -1mol-1) Questions-3 [A] (i) An element atomic mass is 60gm/mol has density of 6.23g-cm -3. If the edge length of its cubic unit cell is 400pm , identify the type of cubic unit cell. Calculate the radius of an atom of this element . (ii) Write the difference between schottky and frenkel defect. (iii) Define Piezoelectricity and give one use of piezoelectric crystal . [B] (i) Calculate e.m.f of the following cell at 298K: ( ) + +( . ) +( . ) + ( ) Given : ( +| ) = . , ( +| ) = . V (ii) What is secondary battery? write the equation for recharging of battery (iii) Define standard hydrogen electrode . Questions-4 [A] (i) The solubility of calcium fluoride ( molecular weight 78) is 1.95x10 -2g/lit at 250C . What is its solubility product ? Will its solubility be more , less or the same in 0.01Msolution of calcium chloride (molecular weight 111) Why? (ii) Calculate the hydrolysis constant , degree of hydrolysis and PH of 0.10M KCN solution at 25oC for KCN ,Ka= 6.2x10-10 (iii) Calculate the PH value of the solution obtained by mixing 50ml of N-HCl and 30ml of N-NaOH solution assuming both to be completely dissociated in normal solution. [B] (i) Consider the following reaction N2O4(g) 2NO2(g), H=58.6KJ (a) Increasing the temperature (b) increasing pressure (c) increasing volume (ii) The equilibrium constant for the reaction H2(g) + I2(g) 2HI(g) , is 49.5 at 4400C. If 0.2 mole of H2 and 0.2 mole of I 2 are allowed to react in a 10lit flask at this temperature , calculate the concentration of each at equilibrium. SECTION B Answer any two questions Question-5 [A] (i)Give the IUPAC name of the following molecule (a) [Co(NH3)4Cl NO2]Cl [Ag(NH3)2]Cl (b) (d) [Ni Cl4]2K2[Ni(CN)4] (ii) Explain the geometry and magnetic character of complex [Cr(NH3)6]3+ (iii) With the help of CFT(Crystal field theory ) predict the number of unpaired electrons in (a) [Fe(H2O)6]2+ [B] (b) [Fe(CN)6]4- (i) Give balance equation for each of the following reaction (a) Fluorine and dilute sodium hydroxide (b) Chlorine and hot concentrated caustic soda (ii) Explain why inter-halogen compounds are more reactive then their constituent elements Question-6 [A] (i) Give reasons for the following: (a)Bond enthalpy of F 2 is lower than that of Cl2. (b)PH3 has lower boiling point than NH 3. (ii) Draw the structures of the following molecules and write hybridization state : (a)BrF 3 (b)XeF 4 [B] (i) Describe the modern method for the manufacture of fluorine (ii) Write one chemical equation to show that SO2 acts as a reducing agents Question-7 [A] (i) Describe the principle controlling each of following process (a) preparation of cast iron from pig iron (b) preparation of pure alumina from bauxite ore (ii) Hydrogen peroxide is an oxidizing as well as reducing agents . Give four reaction to justify the statement. Give its two important uses. [B] (i) KMnO4 acts as a strong oxidizing agent in acidic, alkaline and neutral medium .Give one example each. (ii) Write the difference between lanthanides and actinides elements (iii) What happen when : (a) K2Cr2O7 react with acidified solution of KI (b) K2Cr2O7 react with acidified solution of FeSO4 (c) K2Cr2O7 react with acidified solution of SO2 SECTION C Answer any two questions Questions-8 [A] (i) Draw the resonating structure of phenol. (ii) Give the reason : (a) Why aniline is less basic than methylamine ? (b) Grignard reagent react only in presence of anhydrous condition [B] (i) Give balanced equations for the following reactions: (a) Chloro benzene to toluene (b) chloro-benzene to DDT (ii) How can the following conversions be brought about? (a) Ethanoic acid to ethylamine. (b) Aniline to benzoic acid. Questions-9 [A] [B] (i) What is a zwitter ion? Represent the zwitter ion of glycine (ii) Write the name of monomers used for getting the following polymers : (a) Bakelite (b) Neoprene (i) Write the following name reaction: (a) Reimer - Tiemann reaction (b) Williamson synthesis (c) Wolf- kishner-reaction. (ii) Distinguish between the pair of organic compounds (a) Acetaldehyde and acetone (b) Phenol and benzoic acid Questions-10 [A] (i) Define the following terms as related to proteins: (a) Peptide linkage (b) Primary structure (c) Denaturation (ii) An organic compound A on treatment with ethanol gives a carboxylic acid B and a compound C. Hydrolysis of C under acidic condition gives B and D. Oxidation of D with acidified potassium permanganate also gives B. B on heating with calcium hydroxide gives E with molecular formula C3H6O. E does not give Tollen s test but reacts with iodine and caustic potash to give a yellow precipitate. (a) Identify A, B, C, D and E. (b) Write balanced equation of E with iodine and caustic potash and name the reaction.
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