IIT-JEE-Chemistry-Mains–2000

MAINS 

Time : Two hours                                                              Max. Marks : 100 
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General Instructions : 
1. There are ten questions in this paper. Attempt all Questions. 
2. Answer each question starting on a new page. The corresponding question number must be written in the left margin. Answer all the parts of a question at one place only. 
3. Use only Arabic numerals (0, 1, 2 ………….9) in answering the questions irrespective of the language in which your answer. 
4. Use of logarithmic tables is not permitted. 
5. Use of calculator is NOT PERMITTED. 
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1. (a) Write the chemical reactions associated with the ‘brown ring test’. 

(b) Draw the structures of [Co(NH3)6]3+, [Ni(CN)4]2– and [Ni(CO)4]. Write

thehybridization of atomic orbitals of the transition metal in each case. 

(c) An aqueous blue coloured solution of a transition metal sulphate reacts with H2S in acidic medium to give a black precipitate A, which is insoluble in warm aqueous solution of KOH. The blue solution on treatment with KI in weakly acidic medium, turns yellow and produces a white precipitate B. Identify the transition metal ion. Write the chemical reactions involved in the formation of A and B. 

2. (a) Give an example of oxidation of one halide by another halogen. Explain the feasibility of the reaction. 

(b) Write the MO electron distribution of O2. Specify its bond order and magnetic property. 

(c) 92238U is radioactive and it emits a and b particles to form 82206Pb. Calculate the number of a and b particles emitted in this conversion. An ore of 92238U is found to contain 92238U and 82206Pb in the weight ratio of 1 : 0.1. The half-life period of92238U is 4.5 × 109 years. Calculate the age of the ore. 

3. (a) (i) Give an example of oxidation of one halide by another halogen. Explain the feasibility of the reaction. 
(ii) Write the balanced chemical equation for developing photographic films. 

(b) Write the chemical reactions associated with the ‘borax bead test’ of cobalt (II) oxide. 

(c) Draw the molecular structures of XeF2, XeF4 and XeO2F2, indicating the location of lone pair(s) of electrons.

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