Download SGBAU (Sant Gadge Baba Amravati university) BSc 2019 Summer (Bachelor of Science) 3rd Sem Chemisty Previous Question Paper
B.Sc. (Part?II) Scmcstcr?III Examination
CHEMISTRY
Time : Three Ilours] [Maximum Marks : 80
Note :? ('1) Question No. l is compulsory.
1. (A)
(B)
(C)
2. (A)
(B)
(C)
(2) Solve ONE question from each unit.
(3) Draw diagrams and give equations wherever necessary.
(4) Use of scienti?c calculator is allowed.
Fill in the blanks :? 4X'/2=2
(i) The property ol?mclals to form thin sheets on hammering is known as
(ii) LiAlH4 reduces the carbonyl group into group.
(iii) The surface tension of liquid ?v? with increase of the temperature.
(iv) The titration between an acid and the base is also called as
Choose the correct altemative :?? 4XLE=2
(i) in conformational analysis of n-bulanc the highly stable conformation is :
(a) Gauche (b) Anti or Skew
(c) Partially Eclipsed (d) Fully Eclipsed
(ii) The hybridisation of carbon and oxygen atoms in carbonyl group is :
(a) SP3 (b) Sp
(c) Sp2 (d) dsp2
(iii) The upper critical solution temperature of Phenol-water system is :
(a) 68.1 (b) 67.8
(C) 68.7 (,d) 67.9
(iv) in gravimetric estimation Ihe unknown compound is analysed by measuring its :
(a) Pressure (b) Voiumc
(c) Density (d) Mass
Answer the following in ONE scmcncc :? 4
(i) What is meant by resolution 1?
(ii) What is phase transition ?.7
(iii) What are optically activecompounds ?
(iv) What is molality ?
UNIT?l
Explain VSEPR theory with suitable example. 4
How will you compare atomic orbitals with molecular orbitals ? 4
Draw molecular orbital energy level diagram of 0; molecule. Calculate its bond order.
4
OR
YBC?15256 l (C0ntd.)
3. (P)
(Q)
(R)
4. (A)
(B)
(C)
5. (P)
(Q)
(R)
6. (A)
(B)
(C)
How will you differentiate bonding and amibonding molecular orbitals ? 4
Discuss (i) metalic luster (iii) Electrical conductivity of metal on the basis of free
electron theory. 4
Discuss the structure of BF; molecule on the basis of VSEPR theory. 4
UNlT?ll
Calculate the mole fraction 01? ethanol and water. if solution contains 6 moles of
ethanol and 3 moles of water 4
Explain the terms :--?-
(i) Normality
(ii) Molality. 4
Discuss the choice of suitablc indicator in strong acid with weak base. 4
()R
Discuss the following steps involved in grax'imelric estimation of Barium as barium
Sulphate :
(i) Precipitation
(ii) Digestion. 4
Write a note on Iodimctry and Iodometry. 4
Explain :?-
(i) End Point
(ii) Molarity. 4
IYNIT?III
Complete the following reactions :
K2C1?2(J7
(i) CHE-CHl?OH+[O] H.
.)_+
0 0
II II 50% N.IOH
(ii) H?C?H + H?C?-H ? .\ ?
'? tr '2 4
How will you prepare acctonc from :
(i) Isopropyl alcohol
(ii) 2, 2-Dichloro propane ?.? 4
What happens when Benzoic acid is treated with :
(i) Ethyl alcohol in presence of cone. H_,SO4
(ii) PCIS in presence of cone. H:S()?1 ? 4
OR
YBC?15256 2 (?0de
7. (P)
(Q)
(R)
8. (A)
(B)
(C)
9. (P)
(Q)
(R)
10. (A)
(B)
(C)
11. (P)
(Q)
How will you prepare Bcnzoic acid from
(i) Bcnzyl alcohol
(ii) Phenyl cyanide. 4
What happens when 7
(i) Ethylene glycol on oxidation with chromic acid
(ii) Lactic acid reacts with ethanol in come. H2804 ? 4
Explain Aldol condensation in Aldehydes and Kctoncs with example. 4
UNIT?IV
Explain the following :
(i) Plane of symmetry
(ii) Centre of symmetry. 4
Assign the following groups in proper priority order according to ?R? and ?S' nomenclature
system :
(i) ~?COOH, ???NHz, ?H, ?CH3
(ii) ?C2H$, ?OH, ?H, ?-CH3 4
What is geometrical isomerism ? Explain with suitable example. 4
0R
Explain the conformational analysis of n-butane with energy level diagram. 4
Explain the terms :
(i) Chirality
(ii) Racemisation. 4
Classify the following compounds into F.-2 type :
Br\ /c1 BK /H CH; {11: /H CHs?C?z CH}
9%; ?4; #2 9%
C113 H CH} Cl CH3 CH} c113 .11
4
UNlT?V
Explain the variation of Gibbs free energy with temperature and pressure. 4
State and explain Ncrst Distribution Law. State the conditions of its validity. 4
What is extraction '? Explain its types. 4
OR
Dcrivc Gibb?s?Duhem equation.
Explain the Phenol-Watcr system. 4
YBC-15256 3 (Conld.)
(R) The Value of Kp for Water gel: reaction
CD(g) 1- 1120(g'1 :~ C?O?g) + 112(g)
is 1.6 x 105 at 25?C. Calcu1ate the standard free energy change ('AG") of the reaction
at 25?C.
(R = 8.314 JK"' mole ') 4
l.'1\'1T?VI
12. (A) How rclativc viscosity of liquid is determined by Ostwald?s Viscomcler ?? 4
(B) De?ne :?
(1) Cell constant
(ii) Molar conductance. 4
(C) 0.5 N solution of salt occupying volume hem'ccn two platinum clcclrodes 0.0172 m
apart and 0.04499 sq m. area has resistance 25 ohm. Calculate equivalcm conductance
of solution. 4
OR
13. (P) What are the advantages of conduclomctric titrations over ordinary Iitrations ?? 4
(Q) Explain the variation 01' speci?c and equix'alcnl conductance with dilution. 4
(R) Describe moving boundary method for determination of transport number. 4
YBC??15256 4 625
This post was last modified on 10 February 2020