BACHELOR OF SCIENCE (B.Sc.) Term-End Examination CHEMISTRY PART - A

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1 CHE-4 BACHELOR OF SCIENCE (B.Sc.) Term-End Examination O December, 2009 O CHEMISTRY O CHE-4 : PHYSICAL CHEMISTRY Time : 2 hours Maximum Marks : 50 Note : Attempt all the parts. Answer five questions from each of the parts A, B, C and D. NA = x 1023 mol - 1; R = K - l mol - 1 PART - A Answer any five questions : 1x5=5 Give dimension of electric conductance. What are the SI units of R? State third law of thermodynamics. Give an example of pseudo First order Reaction Which crystal system is given by axes a # b # c and angles a )3 y 90? What are the physical states of the dispersed phase and dispersed medium in a foam? 7. State Hess's law of constant heat summation. CHE-4 1 P.T.O.

2 PART - B Answer any five questions : 2x5=10 Calculate the molar enthalpy of vaporization of CC14 which boils at 350 K. Why is the liquefaction of gases easier at low temperature and high pressure? Concentrated.H 2SO 4 contains 98% acid by weight. Its density is 1.85 x 10 3 Kg m-3. Calculate its molarity. State Kohlrausch's law of independent migration of ions. Write an expression for the half cell reaction and half cell potential for the following redox system : Pt(olCr2072- (C1), Cr3+ (C2), H (C3) Describe the photosensitisation process. 14. Predict whether the process. CcI4 (I) + H2 (g)--->hc1 (g)+ CHc13(1) is spontaneous at 298 K under standard state conditions. At 298 K, Or H = KJ and Or S =41.50 JK-1 for this reaction. CHE-4 2

3 PART - C Answer any five questions : 3x5= Calculate the ratio Ump : u Urms for a gas of molar O mass M m. Does the value of this ratio depend on '111 O temperature? O 16. Write the phase rule expression and explain the terms involved. What is Jule Thomson effect? Explain its importance in the liquification of gases. An aqueous solution containg 5.00 x 104 Kg of a solute in 4.00 x 10 2 Kg of water was found to freeze at K. Calculate the molar mass of the solute (Molar enthalpy of fusion of ice at its melting point ( K) = 6021 Jmol4). State the Raoult's law. Give any two differences between ideal and non-ideal solutions. What is a buffer solution? Give any two examples. 21. Addition of sodium chloride solution to gold sol results in its coagulation. But if its reaction is carried out in the presence of a certain amount of soluble starch, precipitation of gold does not take place. Explain. CHE-4 3 P.T.O.

4 PART - D Answer any five questions : 4x5=20 Describe the carnot cycle. Explain the terms : lattice, and Unit cell. Indicate the Miller indices of crystal plane which make intercepts 2a, 3b and 2c. 24. Explain the following : It is easier for gases to be compressed than liquids. Viscocity of Water at 373 K is Y6 of its viscosity at 273 K. 25. The intrinsic viscosity of a given polymer sample is 0.96 dm3 kg -1. If the value of K and oc are 1.2 x 10-4 dm3 Kg -1 and 0.75, respectively, find the relative molecular mass of the polymer. 26. The decomposition of hydrogen iodide on gold at 32.3 k is zeroth order reaction and the rate constant is 1.20 x 10 4 Ms-1. (a) If the initial concentration of HI is 0.500M, calculate its concentration after 3.00 x 103s. CHE-4 4

5 (b) How long will it take for all the hydrogen iodide to decompose? 27. (a) State Le chatelier's principle. Illustrate it by giving a suitable example. (b) Define ph of a solution. What will be the ph of an acidic solution having hydrogen ion concentro of 0.01M? 28. Briefly explain the following process : Isothermal process Adiabatic process (c) Isobaric process (d) Isochoric process - o 0 o - CHE-4 5 P.T.O.

6 (1011 R-110ch twin ITNIT Nto-cit, 2009 tt1i 41 gooi Tft.7W.V.-4 : eltrff' 04fet : 2 liu2 3.7fWdri viz Tr9ft sinff div Orviq /7&iW 9171T `w; 'W I, 7T atk 'Tr' yew ' stql7 thth c9r4 NA = x 1023mo1 1; R = JK-l mol - I strtr - `w' I0).6 siq-i 37( 0Ni / lx5=5 licichcti fql:r4 \-3K R SI iita ch AzfT t? dm-ivtro chl "WI tri g 1: fotir I oqi-f '51411 eted atin-711 r 3citur q11,=r 3.70a b catitcril uil a P r 90 TURbOf*-1Z-F TITT4 Aid( t? Tag qraiff 3n-gm 3 t trft#eur? 7. 'WT ft el7 1 iilg7 CHE-4 7 P.T.O.

7 Ora 377 dth q'irvn / 2x5=10 CCL4 air 01-1 q dl ch 350 K 774- a1 1 ITY CT-4W LI itch Fri d I.414 WE -d1t i 7cr 3tc1 ERZitci.N't? Tffkff t-k-t-ilftch % 3-11= tl dtichl N-Iccl 1.85 X103 Kg m 3 t I 3W*1 lt-d-cdt LiRchrrid RI 3T7M (-1(11 'Ird q lkidl chlritidm i g 4-1 tfur -1-1 tg d 3Ttrq-zrIcr-4zr f9--* Fr* 3Ttf-ri 3Tfif-*-zrr 3t1T 3Ttf A- : Pt(s) 1Cr (C1), Cr3+ (C2), H + (C3) N chl q l ta 4,10 cht u l uchii it qui-1 WIC4R I 14. AzfT aifilf* K ": cil 31-4R-1T zff -0 I Cc14 (1) + H2 (g) >HC1 (g) + CHc13(1) fq-zu 298 K atfitftzir t f7 A r H = KJ p r S =41.50 JK-1 CHE-4 8

8 ITur - `Tr' drk vfq / 3x5=15 Tfto7 q f Mm ar 9t fmy. ump : Urms arl-crru tifichrod-1-r--a-r I ail l77*r Tim -a-rct fff9f7 cracti t? 171-dT-QTT oiaon -FR 317 1:14 34T4 girl owstif WI-4R I 4-wcf t eq l(sq l `I qzfr t? -k <=1,J 1 Tfrk 4.00 x 10-2 Kg AO x 10-4 Kg -F-4-4 3fTli -01-zif trfl* K tl d7 q ,archrzicr ( K) 371k 4I+ Ic i 14i 1c J mo/-1 t I fldr.e. ri g41 fffrinr IaTT-0 3-1t{ farlel.wl ircitft fq-0717 fir t? T1-1 t dctui qlr,,n I 21. wit 41(1 411s1i-i rtts fad9- frr-o-rk 74 3-Ichr 4q1 t1 f irq T{,4 atfif-*-zrr f-*-tft fq---z:f 7T-4 4-I NT TC1r1:9-Trff 4 f*--zrr 31* t 1.41(9,41 1-r--A-R CHE-4 9 P.T.O.

9 turtt - `Tr' drk 4x5=20,4111 au -I --rr7 I 'loan ogitsql.41 A7 I3.1f-*--F cici fri d7 tci chich f7trk 3-ti:eis 2a, 3b 3 2c t I 24. P1 Sriftcict ot4rseat F : ch) gal 31*1 31-f'4 3TR:rit 441rscf fir t I 373 K 'TT ch K tr{ ea y6 ctei) t? 25. f-* {tk t c ch'i qqfricil 0.96 dm3 kg i t I q rq 1 K 3T «ITN * I-RI: 1.2 x 10-4 dm3 Kg { 0.75 t 311tfk-TW 7fici K 'TT il(-5 'TT 11, FhT7 3376ra7 34.f4T-f 7fT t TT fi 1.20 x 10-4 * I. (a) irq 3Trzt-zro ilqcti 0.500M t 3.00 x 103s T-q tai ai 41U111 CHE-4 10

10 (b) Tfvf i li atrzit3i-crerz-i-4-r-"*79-ftritzr 0 4 I li? 27. (a) T-711-F ffz r-q7 3qltuf gri Ttr*-1- owsif wifqv (b) ft-ft fd-67:17 t ph,iritpert q'11,. I omm iiiq cn.:q 31T rirt fq-d-zri ph fwuffr iln? cf-gwitt-A-141:trwrTcr-4: kii-mil 517b :14 N*)+-1 (c) 111:grA. 514 (d) wilidi-i ch 51t)11 - c CHE-4 11

8. Relax and do well.

8. Relax and do well. CHEM 15 Exam II John II. Gelder March 4, 1999 Name TA's Name Lab Section INSTRUCTIONS: 1. This examination consists of a total of 7 different pages. The last two pages includes a periodic table, a solubility