IIT-JEE-Chemistry-Mains-2003

Mains

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Note : Question number 1 to 10 caries 2 marks each and 11 to 20 carries 4 marks each. 
  
1.         Calculate the molarity of water if its density is 1000 kg/m³. 

2.         The average velocity of gas molecules is 400 m/sec. Calculate its rms velocity at the same temperature. 

3.         Write down the heterogeneous catalyst involved in the polymerization of ethylene. 

4.         Which one is more soluble in diethyl ether anhydrous AICI₃ or hydrous AICI₃? Explain in terms of bonding. 

5.         Using VSEPR theory, draw the shape of PCI5 and BrF5. 

6.         A racemic mixture of (+) 2-phenyl propanoic acid on esterification with (+) 
2-butanol gives two esters. Mention the stereochemistry of the two esters produced.

7.         Wavelengths of high energy transition of H-atoms is 91.2nm. Calculate the corresponding wavelength of He atoms. 

8.         Match the K_a values 
 

	Ka
(a) Benzoic acid      (b) O2N--COOH      (c) CI--COOH      (d) H3CO--COOH      (e) H3C--COOH	3.3 × 10-5     6.3 × 10-5     30.6 × 10-5     6.4 × 10-5     4.2 × 10-5

 
 9.         Write down reactions involved in the extraction of Pb. What is the oxidation number of lead in litharge? 

10.       Following two aminoacids liosine and glutamine form dipeptide linkage. What are two possible dipeptides? 
  
                       NH₂                          NH₂ 
                      |                             |
                 /\/\/\            +              /\/\
            H₂N       COOH             HOOC     COOH 
  
11.       (a) You are given marbles of diameter 10 mm. They are to be placed such that their centres are lying in a square bound by four lines each of length 40 mm. What will be the arrangements of marbles in a plane so that maximum number of marbles can be placed inside the area? Sketch the diagram and derive expression for the number of molecules per unit area. 
  
            (b) 1 gm of charcoal adsorbs 100 ml 0.5 MCH₃COOH to form a monolayer, and thereby the molarity of CH₃COOH reduces to 0.49. Calculate the surface area of the charcoal adsorbed by each molecule of acetic acid. Surface area of charcoal = 3.01 × 10² m²/gm. 
 
12.       (a) Will the pH of water be same at 4^oC and 25^oC? Explain. 
            (b) Two students use same stock solution of ZnSO₄ and a solution of CuSO₄. The emf of one cell is 0.03 V higher than the other. The conc. of CuSO₄ in the cell with higher emf value is 0.5 M. Find out the conc. of CuSO₄ in the other cell (2.203 RT/F = 0.06). 
 
13.       Convert 
                                                                  F
                                                                 /
            (a)          COOH-      →    COOH- 
                            
                 (in not more than 3 steps) 
                                                                                  
  
            (b)            COOH-          →      Aspirin 

14.       There is a solution of p-hydroxy benzoic acid and p-amino benzoic acid. Discuss one method by which we can separate them and also write down the confirmatory tests of the functional groups present. 

15.       A(C₆H₁₂) --HCl--> (B + C) 
                                        (C₆H₁₃CI) 
  
            B -- alc KOH --> D (isomer of A) 
  
            D -- ozonolysis --> E      (it gives negative test with Fehling solution but
                                               responds to idoform test) 
  
            A  -- ozonolysis -->  F + G  (both gives positive Tollen's test but do not 
                                                 give idoform test) 
  
            F + G -- conc. NaOH --> HCOONa + a primary alcohol 
  
            Identify to A to G. 
 
16.       Identify the following : 
            
          Na₂CO₃ -- SO₂ --> A  -- Na₂CO₂ --> B -- Elemental S / Δ --> C  -- I₂ --> D 
            
          Also mention the oxidation state of S in all the compounds. 
 
17.       Write the IUPAC nomenclature of the given complex along with its hybridization and structure. K₂[Cr(NO)(NH₃)(CN)₄], m = 1.73 BM. 
  
18.       A mixture consists A (yellow solid) and B (colourless solid) which gives lilac colour in flame : 
            (a)       Mixture gives black precipitate C on passing H₂S(g). 
 
(b)       C is soluble in aqua-regia and on evaporation of aqua-regia and adding SnCI₂gives grayish black precipitate D. 
The salt solution with NH₄OH gives a brown precipitate. 

(i)            The sodium extract of the salt with CCI₄/FeCI₃ gives a violet layer. 
(ii)          The sodium extract gives yellow precipitate with AgNO₃ solution which is insoluble in NH₃. Identify A and B, and the precipitates C and D. 
  
19.       (a) Match the following if the molecular weights of X, Y and Z are same 
 

 
(b) C_u value of He is always 3R/2 but C_u value fo H2 is 3R/2 at low temperature and 5R/2 at moderate temperature and more than 5R/2 at higher temperature explain in two to three lines. 

20.       (a)       H₂C            CH₂ 
                            \//\//
                             |
                           OH 
            Write resonance structure of the given compound. 

(b) Compound A of molecular formula C₉H₇O₂CI exists in ketoform and predominantly in enolic form 'B'. On oxidation with KMnO4, 'A' gives m-chlorobenzoic acid. Identify 'A' and 'B'.