# IIT JEE 1996, CHEMISTRY

## Instructions

1. The time limit is three hours.
2. Maximum marks - 100.
3. There are Twenty questions in 'this paper. Answer to each new question should begin on a new page.
5. Answer must be written only in the language of your choice as shown on the Admit Card.
6. Use of only lndo-Abrabic numerals, (0, 1, 2, 3 ............ 9) is allowed in answering the questions irrespective of the language in which you answer.
7. There is no negative marking.
8. Numbers in brackets on the right hand margin indicate the marks for the corresponding question.
9. Answer all parts of a question at one place.
10. Use of logarithmic table is permitted.
11. Use of slide rule/calculator is not permitted.

## Useful Data

### Question 1

(i) A mixture of ideal gases is cooled upto liquid helium temperature (4.22 K) to form an ideal solution. Is this statement true or false ? Justifiy your answer in not more than two lines.

(ii) Calculate the wave number for the shortest wavelength transition in the Balmer series of atomic hydrogen.

(iii) The rate constant, the activation energy and the Arrhenius parameter of a chemical reaction at 25󿼇C are 3.0x 10-4 s-1, 104.4 kJ mo1-1 and 6.0 x 1014s -1 respectively. The value of the rate constant as T → &infin is:

(a)2.0 x 1018s -1
(b)6.0 x 1014s -1
(c)Infinity
(d)3.6 x 1030s -1

(iv) The orbital angular momentum of an electron in 2s orbital is:

(a)${\displaystyle {\frac {1}{2}}{\frac {h}{2\pi }}}$
(b)${\displaystyle {\frac {h}{2\pi }}}$
(c)Zero
(d)${\displaystyle {\sqrt {2}}{\frac {h}{2\pi }}}$

### Question 2

5 marks A 3.0 g sample containing Fe304, Fe203 and an inert impure substance, is treated with excess of KI solution in presence of dilute H2SO4. The entire iron is converted into Fe2+ along with the liberation of iodine. The resulting solution is diluted to 100 mL. A 20 mL of the diluted solution requires 11.0 mL of 0.5 M Na2S203 solution to reduce the iodine present. A 50 mL of the diluted solution, after complete extraction of the iodine required' 12.80 mL of 0.25 M KMnO4 solution in dilute H2SO4 medium for the oxidation of Fe2+.

### Question 3

What is your name? isbah kiran

### Question 4

(i) A metallic element crystallises into a lattice containing a sequence of layers of ABABAB ......... Any packing of spheres leaves out voids in the lattice. What percentage by volume of this lattice is empty space? (ii) The standard molar enthalpies of formation of cyclohexane (1) and benezene (1) at 25󿼇C are -156 and + 49 kJ mol -! respectively. The standard enthallW of hydrogenation of cyc. lohexene (1) at 25󿼇C is-119 kJ tool -1 . Use these data to estimate the magnitude of the resonance energy of benzene.