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Biju Patnaik University of Technology 2008-2nd Sem B.Tech (B Tech) , chemistry-I . - Question Paper

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BPUT(B Tech) , second semester chemistry-I ques. paper.

Total number of prin ted pages -7 B. Tec h

BSCC 2101

Second Semester Examination - 2008 CHEMISTRY - I

Full Marks-70 Time: 3 Hours

Answer Question Afo. 1 which is compulsory and any five from the rest.

The figures in thQ right-hand margin indicate marks,

(h = 6,626 x 10 Js. Mass of e = 9.1 x 1CT³¹ kg_r e = l.6 x f0¹⁹C. c = 3x10 m/s, N = 6.023 xK)*³, ft = 8.314 JK-Vmol)

1,, Answer in brief : 2xT0

(aj Write the SchrOdinger time independent wave equation. Explain the terms.

(b) If the wavelength of an electron its one nm, what is the velocity of the electron ?

pxo.

(c) The triple point of one component system is invariant Explain.

{d) Why is AgCl less soluble in AgN0₃ than in pure water ?

2.

(e) Calculate the number of atoms per unit cell of hexagonal cell.

(f) Explain why increase of temperature invariably increases the rate of reaction.

(9) Why phenolphthalein is not a suitable indicator lor titration of HCI against NH₄OH ?

(h) Out of Zn, Ni, 2n+, Ni*² Which is IWL

(i) strongest oxidizing agent and

(ii) strongest reducing agent ?

(E :Zn+/Zn = -0.763V & NiV/Ni = -0.25 V)

(0

For the reaction 2 Nal (aq) + Br_a (g)

2NaBr (aq) + l₂(g). What is the effect on

the reaction rate if some argon are mixed

3.

with bromine ? '

(j) Write down the cell reaction for Pt j H₂(1 atm) | HCI(m) f AgC! j Ag.

(a) Which of the following is/are acceptable wave function or not ? Explain with reasons. (V vs x) 3

i/

(i) <i

(b) Explain how black body radiation led to failure of classical mechanics. 4

(c) Light of 350 nm strikes a metal surface with a work function of 3.2eV.Calculate

(i) the kinetic energy of most energetic electron and

(ii) the stopping potential. 3

(a) Which has more dissociation energy: 0₂ or 0₂+ ? Discuss on the basis of MO theory. 4

(b) Explain the terms conductor, insulator and semiconductor on the basis of molecular orbital diagrams. ₄

(c) Why magnesium behaves as a metal even if it has filled orbitals ? ₂

(bj

Three uni-univalent ionic solids AB, AC and AD are composed of ions having following radii: A* = o.9nm, B- = 0.9 nm, C =1.8 nm, D~-2.7 nm. Predict the structure and coordination of each solid.

3

(c) Discuss about common defects found in

solids.

4

(a) What is a storage cell ? Write down, .the reactions taking place during charging of

lead storage cell. ₂

The emf of the cell SCE11 AgCI(satd) | Ag was 0.26V at 25C. Find out the solubility of AgCI.(E: SCE=0.2415, Ag+/Ag=0.8V)

3

(c) What is quinhydrone ? How can be pH of

an unknown solution be found out using this electrode ? A quinhydrone electrode was coupled with another electrode in a BSCC 2101 5 _pro

(a) Draw a neat diagram and discuss the sulphur equilibrium phase system. 5

(b)

Calculate the number of phases, components and degrees of freedom for a -mixture of n₂, h₂ and ammonia a|\Af| temperature at which equilibrium N_s(g) J " 3H₂(g} -*2NH₃(g) fe reacf₍|y established.

(b)

(c)

What are the characteristics of a g₀₀d

catalyst ?

2

(a)

A substance exists in two allotropic forms rad' ^rad'^{US =} -^3nm> ^and P(BCC, .

ad,_us _ ₀._{37nni) Rnd ou( the rafo}

ineir densities,(a/|3j *

^BSCc 2101 ³

<a)

solution of pH5.6- Find out the potential of the unknown elect rode. (E cell 0-123V, qutnhydrone = 0.699V) 5

8

7 (a) Derive an expression for rate constant of a second order reaction in which both the reactants are different. 4

(b)

(b) The decomposition of a gaseous substance AB(g) -> A(g) + B(g) follows first order kinetics. Calculate 3

(C)

(i) the rate constant if pressure of *WL falls from 0.62 atm to 0.44atm in

50 seconds and

(ii) pressure of AB after 75 seconds at the same temperature.

(c) A first order reaction has rate constant equal to 1.5 x10~⁴ sec"¹ at 300 K and 7.5 x10"⁴ sec'¹at 320 K. Calculate the activation energy and the frequency factor.

3

Calculate the change of Gibbs and Helmholtz free energy when four moles of an ideal gas are expanded isothermally

and reversibty from 5 atm to 1 atm at 300 K;

3

The ionization constant for a certain acid HA is 4.5 x10'⁴at 298 K. What concentration of acid would be required to produce 1H₃CT] of 3 x10~³ M ? 3

Kp for SO_z(g) + y₂ 0₂(g) S0₃(g) is 1.7 xl 0²¹ at 300 K. Calculate Kp and Ke for 2SQ₃(g) 2SO_z(g) + O_z(g). 4

BSCC 2101

BSCC 2101 6 Contd,

-C