No. of Printed Pages : 19. B.Sc. Examination CHE-01 : ATOMS AND MOLECULES AND CHE-02 : INORGANIC CHEMISTRY

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1 No. of Printed Pages : 9 B.Sc. Examination 07E30E3 June, 05 CHE-0 : ATOMS AND MOLECULES AND CHE-0 : INORGANIC CHEMISTRY Instructions : (i) CHE-0/0 Students registered for both CHE-0 and CHE-0 courses should answer both the question papers in two separate answer books entering their enrolment number, course code and course title clearly on both the answer books. (ii) Students who have registered for CHE-0 or CHE-0 should answer the relevant question paper after entering their enrolment number, course code and course title on the answer book. lt. 77 Tft. Tift4n L3, V.t.-0 : TRIT9 3I 39 Tft.7w.i.-0/0 : 3TMT4f4W TigziR crri : (i) 07V R7.7W.i. -0 atk Acrd.f. -0 Err<TATII cam{' 4 d g 3777-raT 3-d-f 3? ;7T aff-f VP/W377 i 3T/7T 33Th77.-W, Wetrgi 905 UPIT weffisi 77T A7 &NW" / (ii) 07V 4:7V.I. -0/ :// 47ḏ.j. -0 ATI7 TW riww 37E4 3* NW - 3Wf, aur-sfir 3777T 33-07* West i As MIT Vieshit q7 R7W-UW PTYW I CHE-0/0 P.T.O.

2 CHE-0 BACHELOR OF SCIENCE (B.Sc.) Term-End Examination June, 05 CHEMISTRY CHE-0 : ATOMS AND MOLECULES Time : hour Maximum Marks : 5 Note : Answer all the five questions. Use the following data wherever required : Mass of electron, me = 9.09 x 0-3 kg Planck's constant, h = 6.66 x 0-34 Js Velocity of light, c =.998 x 08 ms- Avogadro constant, NA = 6.0 x 03 mo-. Answer any two parts : (a) (b) Why is the wave nature of matter not apparent in our daily observations? What is the degeneracy of the 3rd energy level of hydrogen atom? (c) What type of radioactive decay changes both the atomic number and the mass number of the parent nuclide? CHE-0

3 . Answer any two parts : 4 (a) What is the reason for the increase in the spectral frequency as n increases? (b) What is a well behaved wave function? (c) Calculate the energy present in one mole of quanta of indigo light with wavelength 430 nm. 3. ' Answer any two parts : 6 (a) What is the nature of hybridisation present in carbon atoms in (i) benzene, (ii) acetylene, (iii) ethane? (b) Using MO theory, write the electronic configuration of 0 molecule. State whether it is paramagnetic or not. Calculate the bond order of 0 molecule. (c) (i) A gaseous molecule is exposed to electromagnetic radiation which changes its vibrational energy. Would any other type of energy also change with it? If yes, name it. (ii) What are the units of rotational quantum number, J? (iii) Why do group frequencies of various functional groups not change much from molecule to molecule? CHE-0 3 P.T.O.

4 4. Answer any two parts : 8 (a) In BF3 and SnC, both, the central atom has three pairs of electrons. According to the VSEPR theory : (i) what are the shapes of these molecules? (ii) what are the expected and actual bond angles between two Sn - Cl bonds? (iii) why is the actual bond angle different from the expected one? (b) (i) An organic compound has Am 400 nm. The absorbance of its solution (c = 3 mg cm-3) was found to be If a test solution of this compound gave an absorbance of 0.50, calculate its concentration. (ii) What are meso isomers? Give an example. Would a meso compound show optical activity? (c) (i) What is ionisation energy? How does it vary in () a period from left to right, () a group from top to bottom? (ii) Calculate the rate constant for the radioactive disintegration of 6 7Co, an isotope used in cancer treatment. It decays with a half-life of 5.6 years to produce 68Ni. CHE-0 4

5 5. Answer any one part : 5 (a) Which of the following combinations of quantum numbers is/are allowed? Give reasons. n mi m s + + (b) (i) Calculate the magnetic moment of Mn+ ion in jub units (Atomic number of Mn is 5). (ii) Write down Born Haber cycle for BaC formation. CHE-0 5 P.T.O.

6 t-rich trft4ti 4, 05 MIRIdoili 4.7V.t.-0: WHIN 37 atni ffsfel : 367W-dxf 3w : 5 adz: mit qfw vzi-j* 3?" er-4c I 46 arrafelw 4.iWild aike Jr-?77 W-47 : mctol (:)4-, me = 9.09x 0-3 kg h = 6.66 x 0-34 Js '47T, c =.998 x 08 ms- 3rd)73). Pvidicb, NA = 6.0 x 03 mor. We - itiril* : () -gra-r4 fflull 4-0 3rt-N 3"MM 7 6? ViTroj err 6(? (ii) r.hki 5Icht s>hich cboi? CHE-0 6 atgrzat A-Ich -eetkil trit-4-4-4

7 . iirrh*z9t tra7 4 () n* qq4 *ITE-7 k. c fi 3Tr-q%*.qq4 ;ft chrul? (W) kic)4,3-ich 04.cWRcil Wirr? () 430 nm *F47i clic) 4.crl uctoi +ilri l'erizq 4 ztrrpra. tifkcboi *rṟ4r 3. f*-74 -rril zut tr-47 : 6 () 4.4. tr-grrtgall 4 dki i44 (ichtul r sicpf :. (ii) \4 - (iii) atuj mq 4 cht4, 0 39 ait et V Al) -ellti rafur 3- Zi 3rj-wWrzi amar 0 ataj atku zrg --gr Trur-4*=ri* (Tr) (i) 4#43 f',46(uf m fd,tufri cta di t Vizn ti4 TEM -4)4. 3T whit cto-4- \i*,3 4 trft-a-jr. \i, 4 ift trft--4-44? e, R-rgr *r-a7 I (ii) eh:dg ti(90-4, J EFT -4) 54)4 WV. attifffzrt Pa? CHE-0 7 P.T.O.

8 4. f f 39T tra7 8 () BF3 3.{ SnC, *-4r4 7:9 TR AIR. t I VSEPR RT-4iff 34TUTT tft () 33 ITT atrt-nzri? Sn Cl atkill arigraff alt-didct, 3T4IT caui qzrr old? ar-clidch 3fl n arlitrfta- atkv Qui AitTqW6loit? (W) (i) 444 4>ct Al Amax = 400 nm I *i4 4)( ard Vinik (c = 3 mg cm 3) ITT IRE I zit -43 zrtrf 7" TRUTT Qci 3T-4Tu& 0.50 t, tifk,:no-i*i-d-r (ii) wq44 it sly t? JcWul tr-a-ri rr AE4 pur ELE4-dr? (TO (i) atram? cbki 5cblt tifkago di* : () 3rr44-4 -( () A 40-k44't (ii) 6 7 Co IrVkic-idci fdereq P-Fk Trim*r-4 Ta Rgri:9-ufq w44,4.)i-r A=r -4-*-rrgr A ra,.4 WE WI F*-TF 5.6 t MTT 4T4 CHE-0 0 Ni 8 8

9 5. 44 kw RFT 3rd ti-47 : 5 () 4-R-liZsm wr/* 4q-Rr/A. Tiz474 TRI tit? chitui ti77 I n m ms (w) (i) mn+ aim Ti //3 444) 4-6 zlatregif tikchl-zio.gn (Mn Ttffmuj 5h Hich 5 t) (ii) BaC -4T4 4 VW( WW CHE-0 9 P.T.O.