BOARD PAPER 2004

Chemistry 2004 Set 1 Subjective Test    (i)        All questions are compulsory. (ii)        This question paper consists of four sections A, B, C and D.               Section A contains 8 questions of one mark each.               Section B is of 10 questions of two marks each.               Section C is of 9 questions of three marks each and               Section D is of 3 questions of five marks each. (iii)       There is no overall choice. However, an internal choice has been provided. (iv)       Wherever necessary, the diagrams drawn should be neat and properly labelled. Section A Question 1 ( 1.0 marks) Mention a large scale use of the phenomenon called ‘reverse osmosis’. Question 2 ( 1.0 marks) Give an example of a pseudo first-order reaction. Question 3 ( 1.0 marks) Mention two properties of acetonitrile because of which it acts as a good solvent. Question 4 ( 1.0 marks) What are the types of lattice imperfections found in crystals? Question 5 ( 1.0 marks) What is the principal ore of Iron? Question 6 ( 1.0 marks) Write the chemical reaction to transform butanal to butanoic acid. Question 7 ( 1.0 marks) Name the type of structure possessed by a unit cell of CsCl. Question 8 ( 1.0 marks) Write the IUPAC name of the following compound: Section B Question 9 ( 2.0 marks) Explain Brownian movement. Question 10 ( 2.0 marks) Distinguish between reaction rate and reaction rate constant (specific reaction rate) of a reaction. Question 11 ( 2.0 marks) Write the cell reactions which occur in lead storage battery (i) when the battery is in use and (ii) when the battery is on charging. Question 12 ( 2.0 marks) Give chemical reaction in support of each of the following statements: (i) The +1 oxidation state gets stabilised progressively from Ga to Ti in Group 13. (ii) All the bonds in PCl5 molecule are not equivalent. Question 13 ( 2.0 marks) Expand DDT. Write its structure. Question 14 ( 2.0 marks) Write the names of reagents and equations in the conversion of (i) phenol to salicyl aldehyde (ii) anisole to p-methoxyacetophenone Question 15 ( 2.0 marks) Write the modes of free-radical polymerisation of an alkene. OR Differentiate between addition and condensation polymers based on the mode of polymerisation. Give one example of each type. Question 16 ( 2.0 marks) Differentiate between Lanthanides and Actinides series. Question 17 ( 2.0 marks) Calculate the density of silver which crystallises in the face-centred cubic structure. The distance between the nearest silver atoms in this structure is 287 pm. Question 18 ( 2.0 marks) Two elements A and B form compounds having formula AB2 and AB4. When dissolved in 20 g of benzene (C6H6), 1 g of AB2 lowers the freezing point by 2.3 Kwhereas 1.0 g of AB4 lowers it by 1.3 K. The molar depression constant for benzene is 5.1 Kkg mol−1. Calculate atomic masses of A and B. Section C Question 19 ( 3.0 marks) Explain the Froth Floatation Method. Question 20 ( 3.0 marks) Conductivity of 0.00241 M acetic acid is 7.896 × 10−5 S cm−1. Calculate its molar conductivity and if for acetic acid is 390.5 S cm2 mol−1, what is its dissociation constant? Question 21 ( 3.0 marks) A reaction is first order in A and second order in B. (i) Write differential rate equation. (ii) How is the rate affected if the concentration of B is tripled? (iii) How is the rate affected when the concentrations of both A and B are doubled? What is the significance of rate constant in the rate expression? Question 22 ( 3.0 marks) How are the colloids classified on the basis of the nature of interaction between dispersed phase and dispersion medium? Describe an important characteristic of each class. Which of these sols need stabilising agents for preservation? Or What are detergents? Give their scheme of classification. Why are the detergents preferred over soaps? Question 23 ( 3.0 marks) Draw a figure to show splitting of degenerate d orbitals in an octahedral crystal field. How does the magnitude of Δ0 decide the actual configuration of d orbitals in a complex entity? Question 24 ( 3.0 marks) Explain the following terms with suitable examples: (i) Frenkel defect (ii) Interstitials Question 25 ( 3.0 marks) Draw the structures of monomers for the following polymers. Also draw the structures of the polymers and uses of: (i) Teflon (ii) PMMA (iii) Buna-S Question 26 ( 3.0 marks) (a) Identify A and B in the following: (i) (ii) Question 27 ( 3.0 marks) Write the IUPAC names of the following: (i) (ii) (iii) Section D Question 28 ( 5.0 marks) (a) Assign appropriate reason for each of the following observations: (i) Anhydrous AlCl3 is used as a catalyst. (ii) Phosphinic acid behaves as a monoprotic acid. (iii) SF6 is not easily hydrolysed whereas SF4 is readily hydrolysed. (iv) No form of elemental silicon is comparable to graphite. (b) Draw the structure of XeOF4 or BrF3. Or Account for the following: (i) Ammonia is a stronger base than phosphine (ii) The tendency to exhibit +2 oxidation state increases with increasing atomic number in group 14. (iii) HF is a weaker acid than HI. Question 29 ( 5.0 marks) (a) How would you account for the following: (i) The transition elements exhibit high enthalpies of atomisation. (ii) The 4d and 5d series of the transition metals have more frequent metal−metal bonding in their compounds than do the 3d metals. (iii) There is a greater range of oxidation states among the actinoids than among the lanthanoids. (b) Write the complete chemical equation for each of the following: (i) An alkaline solution of KMnO4 reacts with an iodide. (ii) An excess of SnCl2 solution is added to a solution of mercury (II) Or An aqueous solution freezes at 272.4 K, while pure water freezes at 273.0 K. Determine (i) the molality of the solution (ii) the boiling point of the solution (iii) the lowering of vapour pressure of water at 298 K [Given Kf = 1.86 K kg mol−1, Kb= 0.512 K kg mol−1 and vapour pressure of water at 298 K = 23.756 mm Hg] Question 30 ( 5.0 marks) Name the products obtained on complete hydrolysis of DNA. Enumerate the structural differences between DNA and RNA. In what way is a nucleotide different from a nucleoside? Illustrate with examples. Or Define and classify vitamins. Name the diseases caused due to lack of any three of them