CSS 2016 Chemistry Combined Papers Past Paper

Paper details

Examination

CSS

Year

2016

Subject

Chemistry

Paper

Combined Papers

Subject type

Optional

Mode

Subjective

Questions recorded from this paper

These 12 question wordings are transcribed from CSS Vista’s structured Chemistry past-paper record for CSS 2016.

1. Q2 · Schrödinger wave equation and its solution for particle in one and three dimensional box(a) What is Schrodinger wave equation? Discuss its importance in quantum (6) chemistry. (b) Solve the Schrodinger wave equation for a particle in three-dimensional box and (8) find the expression for the energy and wave function. (c) What is a well-behaved function? What are the requirements of a physically (6) acceptable wave function?
2. Q7 · half-life(a) What are lanthanides? How are these extracted from their ores? (10) (b) What is decay law? How half-life and decay constant are related with each (5) other? Roll Number
3. Q3 · transition state theory(a) What is Gibbs free energy? Discuss its significance in chemistry. (6) (b) Give a brief account of transition state theory indicating its advantages over (8) collision theory. (c) Explain 3rd law of thermodynamics. How this law is useful to determine the (6) absolute value of entropy?
4. Q4 · Catalysis(a) Define and explain Langmuir adsorption isotherm. What are its limitations? (8) (b) What is acid-base catalysis? Discuss its significance in chemistry. (6) (c) What is Phase rule? Discuss its application in one component system. (6)
5. Q5 · solubility product(a) What are solubility product and common ion effect? Discuss their significance in (8) chemical analysis (b) Valence shell electron pair repulsion theory can be used to predict the shapes of (7) molecules. Using this theory explain the shapes acquired by BF3 and IF5. (c) Explain why HSH bond angle in H2S is slightly less than the tetrahedral angle (5) 109.5
6. Q6 · Theories of coordination complexes(a) Describe main features of crystal field theory, How this theory explains colour (10) of coordination complexes? (b) Write the electronic configuration for each of the following: (4) Ni2+ , Cu, Mn 2+ , Cr 3+ (c) What is John-Teller theorem? Explain its significance in coordination chemistry. (6)
7. Q3 · Dipole moment(a) How would you synthesize each of the following molecule from an alkene of appropriate (8) structure (structure of your choice). Br Br (i) HC(H 3C) 2 CH CH3 (iii) H3CH 2CH 2C CHCHCH 2CH 2CH 3 (ii) H2CCl CH (iv) O (b) Write the expected major product of the reaction of propyne with each of the following (6) reagents. (i) Cu2Cl2, O2, pyridine (iv) H2O, HgSO4, H2SO4 (ii) Na, ND3 (v) Di-isoamylborane, then NaOH, H2O2 (iii) [(CH3)2CHCH2CH2]2BD (vi) Di-isoamylborane, then CH3CO2D then CH3CO2H (c) Starting with benzene, design reasonable syntheses of each of the following compounds. (6) (i) (iii) CH3 (ii) (b) Draw the structures of the following molecules: (10) (i) 5-(2,2-Dimethylpropyl)nonane (vi) 4-(2-Ethylbutyl)decane (ii) 2,3-Dimethylhept-3-ene (vii) 5-Ethyl-4,6-dimethylhept-4-en-2-yne (iii) 1-Chloro-1-methoxy-2- (viii 5,5-Dichloro-3-methylhepta-3,6- methylbut-1-ene dien-1-yne (iv) 6-Chloro-2-nitrooct-1-en-3-yne (ix) 6-bromo-5-chloro-9- nitropentadecane (v) 8-Chloro-7-methoxy-5-methyl- (x) 6-chloroocta-1,3-diyne 4-nitroundec-5-ene (c) (i) The structure() given below has significant dipole moment. Which end of (2) the molecule would you expect to owe positive charge, and which tend to be negative. (    ii) The structure() given below is a component of certain oral contraceptives: (3) Locate in this structure an example of each of the following bonds or atoms  A highly polarized covalent bond  Sp-hybrid carbon atoms  A nearly unpolarized covalent bond
8. Q5 · Chemistry of Functional Groups(a) (7) the Consider the reaction of bromocyclohexane with each of the four reagents below, and answer answer the questions below. Also write down the reaction mechanism in each case. H2O OH CH3COOH CH3COO (i) (ii) (iii) (vi) (i) What is the most important type of reaction mechanism in each case? (ii) Which reagent gives the most elimination product? (iii) Which reagent is most useful in synthesizing the alcohol? (b) Evaluate each of the possible alcohol syntheses below as being good (the desired (5) alcohol is major or only product), not so good (the desired alcohol is a minor product, or worthless). (i) CH3CH2Cl CH3CH2OH (iv OH-, H2O,  NC HO I OH OH-, H 2O,  (ii) H3C CHCH3 H3C CHCH3 OH-, H2O,  OH-, H2O,  (v) (iii H3C OCH3 CH3OH (c) Write the major product(s) of each of the following reactions. It is implied that (8) aqueous work-up has taken place in all those cases that require it to obtain the organic product. BrMg (CH3CH2)O 1. LiAlD4 + 2. H+, H2O H3C CHCH3 (i) (iii) Br LiAlH4, (CH3CH2)O H 3C H2 , Pt (ii) O (iv) O
9. Q6 · Stereochemistry(a) The two isomers of carvone are given below. Which is R and which is S? (2) (+)-Carvone ()-Carvone (b) The structure of compound given below is a sugar called ()-arabinose. Its (3) specific rotation is 105 ̊. ()-arabinose (i) Draw enantiomer(s) of ()-arabinose (ii) Draw diastereomer(s) of ()-arabinose (iii) Does ()-arabinose have any optically inactive diastereomers? If it does, draw one. (c) Assign E,Z designation to the following structures. (7) (i) (v) H3C : H3C : (ii) (vi : H H H c (iii) (v CH3 H3CH 2CH 2CH 2C O (iv) (d) Draw the structures of the product(s) described for each reaction. Specify all (8) aspects of the stereochemistry. (i) Stereospecific anti addition of bromine to cis- and trans-cinnamic acid. (ii) Methanolysis of S-3-bromooctane with 6% racemization. (iii) Stereospecific syn thermal elimination of acetic acid from 1R,2S- diphenylpropyl acetate (iv) Stereoselective epoxidation of bicyclo[2.2.1]hept-2-ene proceeding 94% fromtheexo face.
10. Q8 · instrumentation and applications of UV/Visible(a). Differentiate following using IR Spectroscopy? (4) i H3C CH3 CH3 ii H3C OH H3C CH3 iii H3C CH2 CH3 H2C CH CH3 HC C CH3 iv H3C CH2 CH2 CH3 (b). What type of electronic transition are possible in the following compounds? (2) (i) Butadiene (iii) Acetaldehyde (ii) Diethyl ether (iv) Trimethylamine (c). How will you distinguish the following compounds using UV/Visible (4) spectrophotometer? (i) and (ii) and (iv) and (iii) CH2 and CH 3 (d). Give the chemical shift of the following compounds for each proton (5) H3C CH3 H CH3 H Cl C C C C C C H3C CH3 (ii) H CH3 ( H CH3 (i) H3C Cl H3C C CH2 Br (v) (iv) CH3 (e). The mass spectrum of compound shows following peaks: (5) m/e= 120, relative intensity=20% (M+ peak), m/e= 105, relative intensity=80%, m/e= 77, relative intensity=96%, m/e= 43, relative intensity=35%. Assign the structure which would be expected.
11. Q2 · MonosaccharidesWrite briefly on the following terms: (2 each) (20) (i) Hyper-conjugation (ii) Aromaticity (iii) Grignard’s reagent (iv) SN1 reaction (v) Molecular chirality (vi) Monosaccharides (vii) Chemical shift (viii Glycolysis (ix) Detergents (x) Friedal Craft alkylation
12. Q7 · Classification of amino acidsWrite a brief account on the following: (5 each) (20) (a) Biological importance of starch (c) Primary structure of Proteins (b) Classification of Amino acids (d) Glycogenesis

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