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Kishor Bisht
The Indian Public School, Dehradun

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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 deg mol 1 = 8.314 J K 1 mol 1 = 0.0821 dm 3 atm K 1 mol 1 1 l atm = 1 dm 3 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. [M] CHCl3 + NaOH (a) Proteins (b) Carbohydrate (c) 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 respectively -3 (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 to 308K, What temperature . If this generalization hold for a reaction in the temperature range 298K 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 [B] assuming both to be completely dissociated in normal solution. (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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