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chemistry question and need a sample draft to help me learn. Basic concepts oof Chemistry Requirements: Å STD: 12th Sci. Prelim Paper Marks: 70 Subject: Chemistry Set 1 Time: 3 hrs. Section A (MCQ & VSA 1 MARKS Questions) Q.1 Select and write the correct answer: 10(i) The fraction of total volume occupied by atoms in a simple cubic is- a. π/2 b. √3 π/8 c. √2 π/6 d. π/6 (ii) Hess law of heat summation includes a. Initial reactants only b. Initial reactants and final products c. Final products only d. Intermediates only (iii) (iv) The molal freezing point constant of water is 1.86 K m⁻¹. If 342 g of cane sugar is dissolved in 1000 g of water, the solution will freeze at a. −360.97 K b. 1.86°C c. −3.92°C d. 2.42°C (v) The electron gain enthalpy of noble gases a. 0 b. less than 0 c. greater than 0 d. either 0 or less than 0 (vi) Strength of acidity is in order a. II > I > III > IV b. III > IV > I > II c. I > IV > III > II d. IV > III > I > II (vii) Most stable oxidation state of Titanium is a. +2 b. +3 c. +4 d. +5 (viii) Acetylcholine is a a. Primary amine b. Secondary amine c. Tertiary amine d. quaternary ammonium salt (ix) The correct order of increasing reactivity of C-X bond towards nucleophile in the following compounds is a. I < II < III < IV b. II < I < III < IV c. III < IV < II < I d. IV < III < I < II Æ (x) Electronic configuration of Cu and Cu⁺¹ a. 3d¹⁰, 4s⁰; 3d⁹, 4s⁰ b. 3d⁹, 4s¹; 3d⁹4s⁰ c. 3d¹⁰, 4s¹; 3d¹⁰, 4s⁰ d. 3d⁸, 4s¹; 3d¹⁰, 4s⁰ Q.2 Answer the following: 8(i) Two liquids A and B on mixing produce a warm solution. Which type of deviation from Raoult’s Law does it show? (ii) What is the rate determining step? (iii) The following pictures show population of bands for materials having different electrical properties. Classify them as insulator, semiconductor or a metal. (iv) Arrange the following in the increase order of boiling points a. 1-Bromopropane b. 2- Bromopropane c. 1- Bromobutane d. 1-Bromo-2-methylpropane (v) Why are ethers insoluble in water? (vi) Why free radical mechanism is known as a chain reaction? (vii) Out of Cu₂Cl₂ and CuCl₂, which is more stable and why? (viii) Write the uses of Glyptal. Section B (SA I - 2 MARKS EACH) Attempt any Eight: 16Q.3 2 NOBr(g) → 2 NO₂ (g) + Br₂ (g), the rate law is rate = k[NOBr]². If the rate of the reaction is 6.5 × 10¯⁶ mol L¯¹ s¯¹ when the concentration of NOBr is 2 × 10¯³ mol L¯¹. What would be the rate constant for the reaction? Q.4 Calculate the spin only magnetic moment of divalent cation of a transition metal with atomic number 25. Q.5 Write two points of difference between properties of phenol and ethyl alcohol. Q.6 What are anode and cathode of H₂ - O₂ fuel cell ? Name the electrolyte used in it. Write electrode reactions and net cell reaction taking place in the fuel cell. Q.7 Identify Thermoplastic and Thermosetting Plastics from the following ----- 1. PET 2. Urea formaldehyde resin 3. Polythene 4. Phenol formaldehyde Q.8 Observe the following equation of reaction of Tollens' reagent with aldehyde. How do we know that a redox reaction has taken place. Explain. Ç Q.9 Define the term: Nanoscience Q.10 What is the mass of Cu metal produced at the cathode during the passage of 5 ampere current through CuSO₄ solution for 100 minutes. Molar mass of Cu is 63.5 g mol¯¹. Q.11 Write structural formulae for: 1-Ethylcyclohexanol Q.12 What are the benefits of green chemistry? Q.13 Q.14 How instantaneous rate of reaction is determined? Section C (SA II - 3 MARKS EACH) Attempt any Eight: 24Q.15 Write the electrode reactions and net cell reaction in NICAD battery. Q.16 Obtain the relationship between density of a substance and the edge length of unit cell. Q.17 Why is there a large difference between the melting and boiling points of oxygen and sulfur? Q.18 Derive the relation pH + pOH = 14. Q.19 Derive the expression for the maximum work. Q.20 What are the differences between cast iron, wrought iron and steel. Q.21 Draw isomers in each of the following Q.22 What is the action of the following reagents on toluene? a. Alkaline KMnO₄, dil. HCl and heat b. CrO₂Cl₂ in CS₂ c. Acetyl chloride in presence of anhydrous AlCl₃. Q.23 What are amines? How are they classified? Q.24 Ksp for a base M(OH)₃ is 2.7 × 10⁻¹¹. Calculate concentration of [OH⁻]. Q.25 Write reaction showing conversion of Acetaldehyde into acetaldehyde dimethyl acetal. Q.26 Explain - Optical isomerism racemic mixture of 2-chlorobutane È Section D (SA II - 4 MARKS EACH) Attempt any Three: 12Q.27 Draw structures of XeF₆, XeO₃, XeOF₄, XeF₂. Q.28 Give evidences to explain aldohexose structure of glucose. Q.29 A solution containing 0.5 g of KCl dissolved in 100 g of water freezes at – 0.24°C. Calculate the percentage ionization of the salt. (Kf for water = 1.86 K m⁻¹). Vapour pressure of pure water at 35°C is 31.82 mm Hg. When 27.0 g of solute is dissolved in 100 g of water (at same temperature), vapour pressure of solution thus formed is 30.95 mm Hg. Calculate molecular mass of the solute. Q.30 When two moles of ethane are burnt, 3129 kJ of heat is liberated. Calculate the heat of formation of ethane, when enthalpy of formation of CO₂ and H₂O are –393.5 and –286 kJ/mol. 2CO + O₂ → 2CO₂, ∆H = –560 kJ Two moles of CO and one mole of O₂ are taken in a container of volume 1L. They completely react to form two moles of CO₂. If the pressure in the vessel changes from 70 to 40 atm, find out the magnitude of ∆U at 500K. Q.31 -------- All the Best -------- Å STD: 12th Sci. Prelims Paper Marks: 70 Subject: Chemistry Set 2 Time: 3 hrs. Section A (MCQ & VSA 1 MARKS Questions) Q.1 Select and write the correct answer: 10(i) To get n-type doped semi-conductor, impurity to be added to silicon should have the following number of valence electrons? a. 2 b. 5 c. 3 d. 1 (ii) Two moles of an ideal gas placed in a vessel at two atm pressure expand into vacuum. The work done is – a. 2J b. 4J c. ∞ d. Zero (iii) Which of the following can not reduce acidified solution of MnO₄⁻ ion a. H₂C₂O₇ b. H₂ c. H(nascent) d. Fe²⁺ ions (iv) Cis - platin is used for the treatment of a. Cancer b. Malaria c. AIDS d. Fever (v) The freezing point of 1% aqueous solution of calcium nitrate will be a. 0°C b. above 0°C c. 1°C d. below 0°C (vi) Nanomaterials are larger than _______ but smaller than ________. a. Single atoms; bacteria and cells b. Bacteria and cells; single atoms c. Bacteria; cells d. Cells, bacteria (vii) Which statement is incorrect? a. Phenol is a weak acid b. Phenol is an aromatic compound c. Phenol liberates CO₂ from NaHCO₃ solution d. Phenol is soluble in NaOH (viii) Methylamine can be prepared by the action of bromine and caustic potash on a. Acetamide b. Propionamide c. Formamide d. Methyl cyanide (ix) At constant T and P, which one of the following statements is correct for the reaction, CO(g) + ½O₂(g) → CO₂(g) a. ΔH is independent of the physical state of the reactants of that compound b. ΔH > ΔU c. ΔH < ΔU d. ΔH = ΔU (x) What is the pH value of 10⁻⁷ M NaOH solution? a. 7 b. 6 c. between 7 to 8 d. between 6 to 7 Q.2 Answer the following: 8(i) Define colligative property of a solution. (ii) Water decomposes by absorbing 286.2 kJ of electrical energy per mole. When H₂ and O₂ combine to form one mole of H₂O, 286.2 kJ of heat is produced. Which law is proved ? What statement of the law follows from it? (iii) Write linkage isomer of [Fe(H₂O)₅SCN]⁺. (iv) What is green chemistry revolution? (v) Why thionyl chloride is most preffereable for the preparation of haloalakanes from alcohols? (vi) Write the IUPAC name of isoprene. (vii) Where are RNA found in body? Æ (viii) Write one limitation of Arrhenius theory of acid and bases. Section B (SA I - 2 MARKS EACH) Attempt any Eight: 16Q.3 At 25 °C a 0.1 molal solution of CH₃COOH is 1.35 % dissociated in an aqueous solution. Calculate freezing point and osmotic pressure of the solution assuming molality and molarity to be identical. Q.4 Calculate standard enthalpy of reaction, 2C₂H₆ (g) + 7O₂ (g) → 4 CO₂ (g) + 6 H₂O(l) Given that ∆fH° (CO₂) = -393.5 kJ mol¯¹, ∆fH° (H₂O) = -285.8 kJ mol¯¹ and ∆fH° (C₂H₆) = -84.9 kJ mol¯¹ Q.5 How will you represent zeroth order reaction graphically? Q.6 Give two chemical reactions to explain oxidizing property of concentrated H₂SO₄. Q.7 Dissociation of HCN is suppressed by the addition of HCl. Explain. Q.8 Aldehydes are more reactive towards nucleophilic addition reactions than ketones. Explain. Q.9 Write IUPAC names of the following Q.10 One mole of a purple coloured complex CoCl₃ and NH₃ on treatment with excess AgNO₃ produces two moles AgCl. Write the formula of the complex if the coordination number of Co is 6. Q.11 The critical degree of polymerization is low for nylon 6 while high for polythene. Explain. Q.12 Define: sustainable development. Q.13 Give reasons: Alkyl halides though polar are immiscible with water. Q.14 Classify the following buffers into different types : a. CH₃COOH + CH₃COONa b. NH₄OH + NH₄Cl c. Sodium benzoate + benzoic acid d. Cu(OH)₂ + CuCl₂ Ç Section C (SA II - 3 MARKS EACH) Attempt any Eight: 24Q.15 Arrange the following carboxylic acids with increasing order of their acidic strength and justify your answer. Q.16 Calculate the emf of the cell Q.17 Explain the trend in following atomic properties of group 16 elements. i. Atomic radii ii. Ionisation enthalpy iii. Electronegativity. Q.18 Give the similarities and differences in elements of 3d, 4d and 5d series. Q.19 Explain why phenol is more acidic than ethyl alcohol. Q.20 Obtain the relationship between ∆H and ∆U for gas phase reactions. Q.21 Write reaction showing the action of the following reagent on propanenitrile- a) Dilute NaOH? b) Dilute HCl? Q.22 How stability of the coordination compounds can be explained in terms of equilibrium constants? Q.23 Write reactions to prepare ethanamine from a. Acetonitrile b. Nitroethane c. Propionamide Q.24 An aqueous solution of a certain organic compound has a density of 1.063 gmL¯¹, an osmotic pressure of 12.16 atm at 25 °C and a freezing point of -1.03 °C. What is the molar mass of the compound? Q.25 Draw a neat diagram for the following: AMP Q.26 Bond dissociation enthalpy of F₂ (158.8 KJ mol¯¹) is lower than that of Cl₂ (242.6 KJ mol¯¹) Why? Section D (SA II - 4 MARKS EACH) Attempt any Three: 12Q.27 Derive the integrated rate law for first order reaction. Q.29 In an ionic crystalline solid atoms of element Y form hcp lattice. The atoms of element X occupy one third of tetrahedral voids. What is the formula of the compound? (X₂Y₃) Iron has a bcc unit cell with a cell dimension of 286.65 pm. The density of iron is 7.874 g/cm³. Use this information to calculate Avogadro’s number. (At-mass of Fe = 55.845 u) Q.30 The molar conductivity of 0.05 M BaCl₂ solution at 25 °C is 223 Ω¯¹ cm² mol¯¹. What is its conductivity? È A current liberates 0.406 g of hydrogen in 2 hrs. Calculate the amount of copper deposited at the electrode when same amount of current is passed through it. Q.31 Primary allylic and primary benzylic halides show higher reactivity by SN1 mechanism than other primary alkyl halides. Explain. -------- All the Best -------- Å STD: 12th Sci. Prelims Paper Marks: 70 Subject: Chemistry Set 3 Time: 3 hrs. Section A (MCQ & VSA 1 MARKS Questions) Q.1 Select and write the correct answer: 10(i) In stoichiometric defects the ratio of positive and negative ions as indicated by chemical formula of the compound: a. Decreases b. Increases c. Remains same d. Cannot be predicted (ii) A system does 100J work on surroundings by absorbing 150J of heat. Calculate the change in internal energy- a. 100 J b. 50 J c. 25 J d. 150 J (iii) Pick the incorrect statement/s regarding catalyst. 1. Small amount of catalyst is capable of changing the rate of reaction to a large extent 2. It initiates the reaction. 3. It does not alter the free energy change ΔG of a reaction. 4. It disturbs the equilibrium. a. 1 and 2 b. 2 and 4 c. 1, 2 and 3 d. 2, 3 and 4 (iv) An aqueous solution of methanol in water has vapour pressure a. Equal to that of water b. Equal to that of methanol c. More than that of water d. Less than that of water (v) The correct order of bond dissociation enthalpy of halogen is a. I–I > Br–Br >Cl–Cl > F–F b. I–I > Br–Br > F–F > Cl–Cl c. F–F > Cl–Cl > Br–Br > I–I d. Cl–Cl > Br–Br > F–F > I–I (vi) Sodium phenoxide reacts with CO₂ at 400 K and 4 to 7 atm pressure to give a. Benzoic acid b. Salicylaldehyde c. Catechol d. Sodium salicylate (vii) The lanthanoid contraction relates to a. Ce, Lu b. Pu, Am c. Np, Pu d. Am, Cm (viii) Isobutyl amine is a a. Primary amine b. Secondary amine c. Tertiary amine d. quaternary ammonium salt (ix) Identify the chiral molecule from the following. a. 1-Bromobutane b. 1,1- Dibromobutane c. 2,3- Dibromobutane d. 2-Bromobutane (x) The magnetic moment of a metal ion of first transition series is 2.83 B.M. therefore, it will have unpaired electrons a. 2 b. 4 c. 3 d. 6 Q.2 Answer the following: 8(i) Name the factors which affect the solubility of a solute in a solvent. (ii) Diazonium salt decomposes as C₆H₅N₂⁺Cl⁻ → C₆H₅Cl + N₂ At 0°, the evolution of N₂ becomes three times faster when the initial concentration of the salt is tripled. What is the order of the reaction? (iii) Why do solids have definite volume? (iv) Which is a better nucleophile: a chloride or an iodide ion? Æ (v) Name the reagent used to convert bromoethane to ethoxy ethene or diethylether. (vi) Define elasticity. (vii) Name the cief ores of the following: (i) Iron (ii) Zinc (viii) Define the term: Monomer Section B (SA I - 2 MARKS EACH) Attempt any Eight: 16Q.3 What is the energy of activation of a reaction whose rate constant doubles when the temperature changes from 303 K to 313 K? Q.4 Aluminium crystallizes in cubic close packed structure with unit cell edge length of 353.6 pm. What is the radius of Al atom? How many unit cells are there in 1.00 cm³ of Al? Q.5 Write structural formulae for: Pentane-1,4-diol Q.6 Why do the cell potential of lead accumulators decrease when it generates electricity ? How the cell potential can be increased ? Q.7 Match the following pairs. Name of polymer Monomer 1. Teflon a. CH₂ = CH₂ 2. PVC b. CF₂ = CF₂ 3. Polyester c. CH₂ = CHCl 4. Polythene d. C₆H₅OH and HCHO 5. Bakelite e. Dicarboxylic acid and polyhydoxyglycol Q.8 Write reaction showing conversion of p- bromoisopropyl benzene into p-Isopropyl benzoic acid (3 steps). Q.9 Explain the role of green chemistry. Q.10 How long will it take to produce 2.415 g of Ag metal from its salt solution by passing a current of 3 amperes? Molar mass of Ag is 107.9 g mol¯¹. Q.11 The boiling point of n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol and tert-butyl alcohol are 118°C, 108° C. 99°C and 82°C respectively. Explain. Q.12 How nanoparticles cause lung cancer? Q.13 Convert the following: Propene to propan-1-ol Q.14 A reaction takes place in two steps, 1. NO(g) + Cl₂ (g) → NOCl₂ (g) 2. NOCl₂ (g) + NO(g) → 2 NOCl(g) a. Write the overall reaction. b. Identify reaction intermediate. c. What is the molecularity of each step? Ç Section C (SA II - 3 MARKS EACH) Attempt any Eight: 24Q.15 Using the relationship between ∆G° of cell reaction and the standard potential associated with it, how will you show that the electrical potential is an intensive property? Q.16 The unit cell of metallic silver is fcc. If radius of Ag atom is 144.4 pm, calculate (a) edge length of unit cell (b) volume of Ag atom, (c) the percent of the volume of a unit cell, that is occupied by Ag atoms, (d) the percent of empty space. Q.17 How are xenon fluorides XeF₂, XeF₄ and XeF₆ obtained? Give suitable reactions. Q.18 What are acids and bases according to Arrhenius theor ? Q.19 Obtain the relation between ∆G and ∆Stotal. Comment on spontaneity of the reaction. Q.20 How catalyst increases the rate of reaction? Explain with the help of potential energy diagram for catalyzed and uncatalyzed reactions. Q.21 Q.22 Write reaction to convert ethylamine into methylamine. Q.23 Explain carbylamine reaction with suitable examples. Q.24 What is the relationship between molar solubility and solubility products for salts given below: i. Ag₂CrO₄ ii. Ca₃(PO₄)₂ iii. Cr(OH)₃. Q.25 Write and explain reactions to convert propan-1-ol into propan-2-ol ? Q.26 Observe the following and answer the questions given below. a. Name the type of halogen derivative b. Comment on the bond length of C-X bond in it c. Can it react by SN1 mechanism? Justify your answer. Section D (SA II - 4 MARKS EACH) Attempt any Three: 12Q.27 Describe the manufacturing of H₂SO₄ by contact process. Q.28 Write a short note on Starch. Q.29 A decimolar solution of K₄[Fe(CN)₆] is 50% dissociated at 300 K. Calculate the osmotic pressure of solution. [R = 0⋅0821 L atm K⁻¹ mol⁻¹] The vapour pressure of pure benzene at 25 °C is 639⋅7 mm Hg and vapour pressure of a solution of a non-volatile solute in benzene at same temperature is 631⋅9 mm Hg. Calculate moles of solute and molality of solution. Q.30 Calculate ∆H for the transformation of one gram atom of rhombic sulphur into monoclinic sulphur. (a) S(rhombic) + O₂ (g) → SO₂ (g), ∆H= –297.5 kJ/mol È (b) S(monoclinic) + O₂ (g) → SO₂ (g), ∆H = –300 kJ/mol Enthalpy of combustion of carbon to CO₂ is – 393•5 kJ mol⁻¹. Calculate the heat released upon formation of 35.2 g of CO₂ from carbon and dioxygen gas. Q.31 -------- All the Best -------- Å STD: 12th Sci. Prelims Paper Marks: 70 Subject: Chemistry Set 4 Time: 3 hrs. Section A (MCQ & VSA 1 MARKS Questions) Q.1 Select and write the correct answer: 10(i) Ice crystalizes in a hexagonal lattice having volume of the unit cell as 132 × 10⁻²⁴ cm³. If density is 0.92 g/cm³ at a given temperature, then number of H₂O molecules per unit cell. a. 1 b. 2 c. 3 d. 4 (ii) The enthalpy of formation for all elements in their standard states is a. unity b. zero c. less than zero d. different elements (iii) Which actinoid, other than uranium, occur in significant amount naturally? a. Thorium b. Actinium c. Protactinium d. Plutonium (iv) According to VBT, which type of bond is present between the ligand and the central metal atom? a. Covalent bond b. Ionic bond c. Co-ordinate bond d. Hydrogen bonds (v) Henry’s law constant for a gas CH₃Br is 0.159 moldm¯³ atm at 250 °C. What is the solubility of CH₃Br in water at 25 °C and a partial pressure of 0.164 atm? a. 0.0159 mol L¯¹ b. 0.164 mol L¯¹ c. 0.026 M d. 0.042 M (vi) Which of the following are nanoscale systems? a. Zero dimensional nanostructures b. One dimensional nanostructures c. Two dimensional nanostructures d. All of these (vii) Conc.H₂SO₄ heated with excess of C₂H₅OH at 140°C to form a. CH₃CH₂−O−CH₂CH₃ b. CH₃CH₂−O−CH₃ c. CH₃−O−CH₂CH₂CH₃ d. CH₂=CH₂ (viii) Which of the following compounds will dissolve in aqueous NaOH after undergoing reaction with Hinsberg reagent ? a. Ethylamine b. Triethylamine c. Trimethylamine d. Diethylamine (ix) For vaporization of water at 1 bar, ∆H = 40.63 kJ mol¯¹ and ∆S = 108.8 J K¯¹ mol¯¹. At what temperature, ∆G = 0 ? a. 273.4 K b. 393.4 K c. 373.4 K d. 293.4 K (x) Which of the following solution will have pH value equal to 1.0 ? a. 50 mL of 0.1M HCl + 50mL of 0.1M NaOH b. 60 mL of 0.1M HCl + 40mL of 0.1M NaOH c. 20 mL of 0.1M HCl + 80mL of 0.1M NaOH d. 75 mL of 0.2M HCl + 25mLof 0.2M NaOH Q.2 Answer the following: 8(i) What is osmotic pressure? (ii) Is the bond energy of all the four C — H bonds in CH₄ molecule equal? lf not then why? How is the C — H bond energy then reported? (iii) Write the formula for tetraammineplatinum (II) chloride. (iv) Name one bacterial disinfectant present in water. (v) What is the order of reactivity of halogen in free radical halogenation? Æ (vi) Write the chemical formula of thermocol. (vii) Name the oxidation product of glucose with bromine water. (viii) Why is KCl solution neutral to litmus? Section B (SA I - 2 MARKS EACH) Attempt any Eight: 16Q.3 The normal boiling point of ethyl acetate is 77.06 °C. A solution of 50 g of a non-volatile solute in 150 g of ethyl acetate boils at 84.27 °C. Evaluate the molar mass of solute if Kb for ethyl acetate is 2.77 °C kg mol¯¹. Q.4 Calculate the amount of work done in the (a) oxidation of 1 mole HCl(g) at 200 °C according to reaction. 4HCl(g) + O₂(g) → 2 Cl₂ (g) + 2 H₂O(g) (b) decomposition of one mole of NO at 300 °C for the reaction 2 NO(g) → N₂ (g) + O₂ Q.5 Distinguish between order and molecularity of a reaction. Q.6 Discuss the structure of sulfure dioxide. Q.7 Why is it necessary to add H₂SO₄ while preparing the solution of CuSO₄? Q.8 Write reaction showing conversion of Benzonitrile into benzoic acid. Q.9 Predict the products for the following reaction. Q.10 The dissociation constant of NH₄OH is 1.8 × 10¯⁵. Calculate its degree of dissociation in 0.01 M solution. Q.11 Complete the following statements a. Caprolactam is used to prepare-------- b. Novolak is a copolymer of -------- and --------- c. Terylene is ----------polymer of terephthalic acid and ethylene glycol. d. Benzoyl peroxide used in addition polymerisation acts as ---------- e. Polyethene consists of polymerised ------------ Q.12 Define catalyst. Give two examples. Q.13 Which one compound from the following pairs would undergo SN2 faster from the other compound of the pair? Q.14 Calculate the pH of 0.01 M sulphuric acid. Ç Section C (SA II - 3 MARKS EACH) Attempt any Eight: 24Q.15 Write the electrode reactions when lead storage cell generates electricity. What are the anode and cathode and the electrode reactions during its recharging? Q.16 A conductivity cell containing 0.01M KCl gives at 25 °C the resistance of 604 ohms. The same cell containing 0.001M AgNO₃ gives resistance of 6530 ohms. Calculate the molar conductivity of 0.001M AgNO₃. [Conductivity of 0.01M KCl at 25 °C is 0.00141 Ω¯¹ cm¯¹] Q.17 Obtain the relationship between the rate constant and half life of a first order reaction. Q.18 Distinguish between - SN1 and SN2 mechanism of substitution reaction ? Q.19 An organic compound gives hydrogen on reaction with sodium metal. It forms an aldehyde having molecular formula C₂H₄O on oxidation with pyridinium chlorochromate Name the compounds and give equations of these reactions. Q.20 Obtain the relationship between ∆G° of a reaction and the equilibrium constant. Q.21 State Hess’s law of constant heat summation. Illustrate with an example. State its applications. Q.22 Draw geometric isomers and enantiomers of the following complexes. Q.23 What is diazotisation? Write diazotisation reaction of aniline. Q.24 Fish generally needs O₂ concentration in water at least 3.8 mg/L for survival. What partial pressure of O₂ above the water is needed for the survival of fish? Given the solubility of O₂ in water at 0 °C and 1 atm partial pressure is 2.2 × 10¯³ mol/L Q.25 Draw a schematic representation of trinucleotide segment 'ACT' of a DNA molecule. Q.26 Define pH and pOH. Derive relationship between pH and pOH. Section D (SA II - 4 MARKS EACH) Attempt any Three: 12Q.27 Explain graphically the effect of catalyst on the rate of reaction. Q.29 An element has a bcc structure with unit cell edge length of 288 pm. How many unit cells and number of atoms are present in 200 g of the element? Gold [atomic radius = 0.144nm] crystallizes in a face centered unit cell. What is the length of a side of the cell? Q.30 The molar conductivity of 0.01M acetic acid at 25 °C is 16.5 Ω¯¹ cm² mol¯¹. Calculate its degree of dissociation in 0.01 M solution and dissociation constant if molar conductivity of acetic acid at zero concentration is 390.7 Ω¯¹ cm² mol¯¹. Calculate molar conductivity of solution of MgCl₂ at infinite dilution from the given data. Q.31 Complete the following reactions giving major product. È -------- All the Best -------- Å STD: 12th Sci. Prelims Paper Marks: 70 Subject: Chemistry Set 5 Time: 3 hrs. Section A (MCQ & VSA 1 MARKS Questions) Q.1 Select and write the correct answer: 10(i) Copper crystallizes in a face-centered cubic lattice with a unit cell length of 361pm. What is the radius of copper atom in pm? a. 157 b. 181 c. 108 d. 128 (ii) If the standard enthalpy of formation of methanol is -238.9 kJ mol¯¹ then entropy change of the surroundings will be a. -801.7 J K¯¹ b. 801.7 J K¯¹ c. 0.8017 J K¯¹ d. -0.8017 J K¯¹ (iii) A first order reaction is 75% complete after 32 minutes and 50% completed in a. 4 minutes b. 8 minutes c. 16 minutes d. 32 minutes (iv) Ebullioscopic constant is the boiling point elevation when the concentration of solution is a. 1m b. 1M c. 1 mass% d. 1 mole fraction of solute. (v) Select the correct decreasing order of electronegativity of halogens. a. I > Br > F > Cl b. F > Cl > Br > I c. F > Br > Cl > I d. I > Br >Cl > F (vi) In the reaction given below, X is C₆H₅MgBr + CH₃OH → X a. C₆H₆ b. C₆H₅OH c. C₆H₅OCH₃ d. CH₃COOH (vii) The outer electronic configuration of Gd (At. No. 64) is a. 4f³5d⁵6s² b. 4f⁸5d⁰6s² c. 4f⁴5d⁴6s² d. 4f⁷5d¹6s² (viii) Isobutylamine is an example of ............ a. 2° amine b. 3° amine c. 1° amine d. quaternary ammonium salt. (ix) Which of the following is a primary halide a. Neo-hexyl chloride b. Secondary butyl iodide c. Tert-butyl bromide d. Iso-propyl iodide (x) The transition elements are more metallic than the representative elements because they have a. The electrons in d-orbitals b. Electron pairs in d-orbitals c. Availability of d-orbitals for bonding d. Unpaired electrons in metallic orbitals Q.2 Answer the following: 8(i) How molar mass of a solute is determined by osmotic pressure measurement? (ii) What are the units for rate constants for zero order and second order reactions if time is expressed in seconds and concentration of reactants in mol/L? (iii) What is the unit cell? (iv) Write IUPAC name of the following compounds Æ (v) Glycerol is highly soluble in both, water and alcohol. How? (vi) Give one example each of copolymer and homopolymer. (vii) Define gangue? (viii) Name the Polymers on the basis of origin. Section B (SA I - 2 MARKS EACH) Attempt any Eight: 16Q.3 In a first order reaction, the concentration of reactant decreases from 20 mmol dm¯³ to 8 mmol dm¯³ in 38 minutes. What is the half life of reaction? Q.4 How many moles of electrons are required for reduction of 3 moles of Zn2⊕ to Zn ? How many Faradays of electricity will be required ? Q.5 Explain why p-nitrophenol is a stronger acid than phenol. Q.6 Under what conditions the cell potential is called standard cell potential? Q.7 What is meant by LDP and HDP? Mention the basic difference between the same with suitable examples. Q.8 Formic acid is stronger than acetic acid. Explain. Q.9 Define: Green chemistry Q.10 Q.11 Write structural formulae for: Methyl vinyl ether Q.12 Explain the steps included in sol-gel process. Q.13 Convert the following: Propene to 1-nitropropane Q.14 Explain with the help of Arrhenius equation, how does the rate of reaction changes with (a) temperature and (b) activation energy. Section C (SA II - 3 MARKS EACH) Attempt any Eight: 24Q.15 What are anode and cathode for Leclanche' dry cell ? Write electrode reactions and overall cell reaction when it generates electricity. Ç Q.16 Niobium forms bcc structure. The density of niobium is 8.55 g/cm³ and length of unit cell edge is 330.6 pm. How many atoms and unit cells are present in 0.5 g of niobium? Q.17 Predict whether the following reactions would occur spontaneously under standard state conditions. Q.18 Sulfides of cation of group II are precipitated in acidic solution (H₂S + HCl) whereas sulfides of cations of group IIIB are precipitated in ammoniacal solution of H₂S. Comment on the relative values of solubility product of sulfides of these. Q.19 Q.20 Explain Ammonolysis of alkyl halides. Q.21 What are cationic, anionic and neutral complexes? Give one example of each. Q.22 Derive the relationship between degree of dissociation of an electrolyte and van’t Hoff factor. Q.23 Write reaction to convert methyl bromide into ethyl amine ? Also, comment on the number of carbon atoms in the starting compound and the product. Q.24 A weak mono acidic base is 10% dissociated in 0.05 M solution. Evaluate the percent dissociation in 0.10M solution. Q.25 Write the names and schematic representations of all the possible dipeptides formed from alanine, glycine and tyrosine. Q.26 Match the column: Section D (SA II - 4 MARKS EACH) Attempt any Three: 12Q.27 Describe the structure of Ozone. Give two uses of ozone. Q.28 Explain the double helix model of DNA. Q.29 What will happen to the boiling point of a solution if the weight of the solute dissolved is doubled but the weight of solvent taken is halved? (a) What is the expected value of van’t Hoff factor for K₃[Fe(CN)₆] ? (b) Acetic acid associates in benzene to form double molecules. What is the value of van’t Hoff factor for it? È Q.30 Find out the internal energy change for the reaction A(l) → A(g) at 373 K. Heat of vaporiza
Ÿon is 40.66 kJ/mol and R = 8.3 J mol⁻¹ K⁻¹. Given : N₂(g) + 3H₂(g) → 2NH₃(g); ∆rH° = –92.40 kJ. What is the standard enthalpy of formation of NH₃ gas? Q.31 What are ligands ? What are their types ? Give one example of each type. -------- All the Best --------