IIT-JEE-Chemistry-Mains-2002

MAIN

Time : Two hours                                                                      Max. Marks : 60

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Instructions 
1.     The Question Paper has 4 printed pages and has 12 questions. Please ensure that the copy of the Question Paper you have received contains all the questions. 
2.     Attempts ALL questions. Each question carries 5 marks. 
3.     Answer each question starting on a new page. The corresponding Question number must be written in the left margin. 
4.     Do not write more than one answers for the same question. In case you attempt a question more than once, please cancel the answer(s) you consider to be wrong. Otherwise, only the answer appearing last will be evaluated. 
5.     Use only Arabic numerals (0, 1, 2 .............9) in answering the questions irrespective of the language in which your answer. 
6.     Use of logarithmic tables is NOT PERMITTED. 
7.     Use of calculators is NOT PERMITTED. 
8.     Both magnitude and direction of vector quantities, if any, in your answer should be indicated clearly. 
9.     Irrational numbers, if any, in your answer need not be expressed in decimal form. 
10.  If the final answer appears in the form of a ratio or a product of two numbers, that need not to be further simplified. 
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1.         Five isomeric para-disubstituted aromatic compounds A to E with molecular formula C₈H₈O₂ were given for identification. Based on the following observation, give structures of the compounds. 
(i)         Both A and B from a silver mirror with Tollen's reagent; also, B gives a positive test with FeCI₃ solution. 
(ii)        C gives positive idoform test. 
(iii)       D is readily extracted in aqueous NaHCO₃ solution. 
(iv)       E on acid hydrolysis gives 1, 4-dihydroxybenzene. 
  
2.         500 mL of 0.2 M aqueous solution of acetic acid is mixed with 500 mL of 0.2 M HCI at 250^oC. 
(i)         Calculate the degree of dissociation of acetic acid in the resulting solution and pH of the solution. 
(ii)        If 6 g of NaOH is added to the above solution, determine the final pH. [Assume there is no change in volume on mixing; K_a of acetic acid is 
1.75 × 10^-5 mol L^-1]. 
3.         Deduce the structures of [NiCI₄]^2- and [Ni(CN)₄]^2- considering the hybridization of the metal ion. Calculate the magnetic moment (spin only) of the species.
4.         The density of the vapour of a substance at 1 atm pressure and 500 K is 0.36 kg m^-3. The vapour effuses through a small hole at a rate of 1.33 times faster than oxygen under the same condition. 
(a)       Determine (i) molecular weight, (ii) molar volume, (iii) compression factor (Z) of the vapour and (iv) which forces among the gas molecules are dominating, the attractive or the repulsive? 
(b)       If the vapour behaves ideally at 1000 K, determine the average translational kinetic energy of a molecule.
5.         Write balanced equations for the reactions of the following compounds with water: 
            (i)         AI₄C₃ 
            (ii)        CaNCN 
            (iii)       BF₃ 
            (iv)       NCI₃ 
            (v)        XeF₄
6.         Identify X, Y and Z in the following synthetic scheme and write their structures. 
                               [i] NaNH₂          H₂/Pd BaSO₄        alkaline KMnO₂ 
     CH₃CH₂C ≡ C - H -------------> X  ------------->  Y  ----------------> Z 
                                   [ii]  CH₃CH₂Br 
            Is the compound Z optically active? Justify your answer.
7.         How is boron obtained from borax? Give chemical equations with reaction conditions. Write the structure of B₂H₆ and its reaction with HCI.
8.         ⁶⁴Cu (half-life = 12.8 h) decays by b^- emission (38%), b⁺ emission (19%) and electron capture (43%). Write the decay products and calculate partial half-lives for each of the decay processes. 
9.         When a white crystalline compound X is heated with K₂Cr₂O₇ and concentrated H₂SO₄ a reddish brown gas A is evolved. On passing A into caustic soda solution, a yellow coloured solution of B is obtained. Neutralizing the solution of B with acetic acid and on subsequent addition of lead acetate a yellow precipitate C is obtained. When X is heated with NaOH solution, a colourless has is evolved and on passing this gas into K₂HgI₄ solution, a reddish brown precipitate D is formed. Identify A, B, C, D and X. Write the equations of reactions involved.
10.       Write the structures of the products A, B, C, D and E in the following scheme. 

              
11.       A biologically active compound, Bombykol (C₁₆H₃₀O) is obtained from a natural source. The structure of the compound is determine by the following reactions. 
(a)       On hydrogenation, Bombykol gives a compound A, C₁₆H₃₄O, which reacts with acetic anhydride to give an ester, 
(b)       Bombykol also reacts with acetic hydride to give another ester, which on oxidative ozonolysis (O₃/H₂O₂) gives a mixture of butanoic acid, oxalic acid and 10-acetoxy decanoic acid. 
Determine the number of double bonds in Bombykol. Write the structures of compound A and Bombykol. How many geometrical isomers are possible for Bombykol?
12.       Two moles of a perfect gas undergo the following processes: 
(a)  a reversible isobaric expansion from (1.0 atm, 20.0 L) to (1.0 atm, 40.0 L); 
(b)  a reversible isochoric change state from (1.0 atm, 40.0 L) to (0.5 atm, 40.0 L); 
(c)  a reversible isothermal compression from (0.5 atm, 40.0 L) to (1.0 atm, 20.0 L); 
(i)   Sketch with labels each of the processes on the same P-V diagram. 
(ii)  Calculate the total work (w) and the total heat change (q) involved in the above processes. 
(iii)  What will be the values of DU, DH and DS for the overall process?