B.Sc. Examination December, 2015 CHE-01 : ATOMS AND MOLECULES AND CHE-02 : INORGANIC CHEMISTRY

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1 1:7173LF.ii2 No. of Printed Pages : 21 B.Sc. Examination December, 2015 CHE-01 : ATOMS AND MOLECULES AND CHE-02 : INORGANIC CHEMISTRY CHE-01/02 I Instructions : (i) Students registered for both CHE-0 1 and CHE-02 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) (ii) Students who have registered for CHE-0 1 or CHE-02 should answer the relevant question paper after entering their enrolment number, course code and course title on the answer book. 41.7r IC Rtii-Git, 2015 Trt.7V.t.-01 : TrITTrui afri : Th. 3M1-4ft ITITER Wi s i i #1:7W ?ift.qV.I. -02 q.t. grqwwiff h"..n 7'4*u - ff, q2.17 TR7-t-iwY dri< dri< , 11/qq5/ T ill z/s~ih f1/51)-cif/y) 7 / Ritqw.e. -01 alt e.7v.i. -02 &Fit * iri, drff -syrffiw Mff ff, 370 dfil WIRT 373M777* 11/qq0,14 ch?5 TWT tilestgi q77t ftl5h-hiy, OW?. I CHE-01 /02 1 P.T.O.

2 CHE-01 BACHELOR OF SCIENCE (B.Sc.) Term-End Examination December, 2015 CHEMISTRY CHE-01 : ATOMS AND MOLECULES Time : 1 hour Maximum Marks : 25 Note : Answer all the five questions. Use the following data wherever required : Mass of electron, m = x kg Planck's constant, h = x Js Velocity of light, c = x 108 ms-1 Rydberg constant, R H = x 107 m-1 1. Answer any two parts : 2 (a) (c) Out of 0 and F, which one has higher ionisation energy? Justify your answer. Write the nuclear reaction responsible for the energy in the Sun. Radius of a cation A+ is 82 pm while that of an anion B- is 164 pm. On this basis, predict the coordination number of cation in AB crystal. CHE-01 2

3 2. Answer any two parts : 4 (a) State Hund's rule and give justification for it. Predict, whether the following molecules. are microwave active or inactive : CC14, HC1, CH3C1 and N2 (c) Calculate the frequency of the radiation required to eject the photoelectrons at a velocity of 5 x 10 6 ms-1 from sodium metal. The threshold frequency of sodium is 4.6 x 1014 Hz. 3. Answer any two parts : 6 (a) (c) Write the molecular orbital configuration of N2 and calculate its bond order. Is it paramagnetic or not? Calculate the wave numbers of first and second spectral lines in the Lyman series of hydrogen atom. Predict the shape of PC1 5 based on VSEPR theory. Explain the type of hybridisation in it. CHE-01 3 P.T.O.

4 4. Answer any two parts : (a) What is binding energy? What are the effects of fi -decay, f + -decay and electron capture on the atomic number Z and the mass number A, of the parent atom? (i) Calculate the force constant for a diatomic molecule if it absorbs radiation at x 10 6 m-1 and its reduced mass is x kg. (ii) A molecule A2B has 3 modes of vibration. Is it a linear or a non-linear molecule? (c) (i) Draw a labelled diagram depicting variation of radial probability density r2r2(r) against (r/a0) for an electron in 2s orbital. (ii) For a molecule A, the plot of total polarisation Pm vs 1 has zero slope while for molecule B, it has a finite positive slope. Out of CHC1 3 and CC14, which one could be molecule A and why? CHE-01 4

5 5. Answer any one part : 5 (a) (i) What is dielectric constant? The capacitance of a capacitor in vacuum is 8.9 x F. When the capacitor is filled with a dielectric, the capacitance is 80.1 x F. Calculate the dielectric constant of the dielectric material N undergoes (a, p) type nuclear transformation. Write the nuclear reaction for the process. 2 (i) Why is not the wave nature of matter apparent in our daily observations? (ii) The lattice enthalpies of NaCl, KC1 and AgC1 are - 787, and kj mo1-1, respectively. Based on these values, arrange them in increasing order of water solubility and justify your answer. 2 (iii) State Beer - Lambert law. 2 CHE-01 5 P.T.O.

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8 4. f*-4-3-ta.31k tr4r : 8 () 4t/4 31A ;Err? TR79 f1 Z I I Z 311-{ 4i.seil A tit fi- 44, fi + - T3 Alch 3TI-TT4 6)01? ur ra4 4) -Pitk A'r177, 7:fg x 106 m-1 'R( T ctrcit att w4,1 Trgrr-4M 50q4iii x kgt I (ii) l 39 A2B 3 cv-14-i fd101i Tf zig trw. 39 t zrr 33-11? q). T 2s *4.T- 4 7C-P-Tff R,N d atilt4 w4r-4-r (r/a 0) * fd'f4 trit4.4q T4TiaT t I eictm I Erg r2r 2(r) (ii) 1 39 A TrT 4't wourm TMtzr gq't Pm Acif4 39 B * 7-4uTaT llf(rfff t I CHC13 WiTT CC14 14 tt) 39 At.)cli? CHE-01 8

9 5. 1%-kft Ta. tr-4r : 5 () (i) 441? -Wt littrfri f-4-41-d 4 ttlitdt 8.9 x F 174 'ilitttq. 4 Truktid Aim t, ttritat 804 x F Alcn t I TOW 'm4 1TUFT *rr-a-r 3 (ii) 1 N, (a, p) Mchit ett4izr 7 ctaci I t I Te ITT * if1t4tat afta-zrr few 2 (w) (i) -srpdfq- * rt-r 3Tri-TM Ter.1(11 -t? (ii) NaC1, KC1 Wan AgC1 TAP* * TIR - 787, Alcich kj mo1-1 t I "F 1491 * 3.11tET fdrzfat * TR 4 &r-gr -pm (ilivw afrk atia Brit (inn) NeR -4C-4R I 2 2 CHE-01 9 P.T.O.