BSc Chemistry SEM II 2016 17 2016-17 Chemistry Paper II R Question Paper - Mumbai University | munotes

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1. Q2 Answers to the same questions must be written together
2. Q3 Figures to the right indicate full marks
3. Q4 The use of long table/non-programmable calculator is allowed
4. Q1 A_ Select the correct option and complete the following statements. 12 marks
   • i. At 298 K, pOH of NaOH of solution is 2.5, its pH is
   • ii. The dissociation constants for some monobasic acids are: = 5.4 X =1.8 X and (Acid)3 = 6.3 X is the weakest acid among them
   • a) (Acid);
   • b) (Acid)2
   • iii. The SI unit of frequency of radiation is
   • a) cm
   • c) Hertz
   • iv. The maximum number of centre of symmetry possesses by any crystal is Vv. The bond angle X — P in PX3 gets reduced
   • a) with increase in electronegativity of halogen atom
   • b) with decrease in electronegativity of halogen atom
   • c) without any effect of electronegativety of halogen atom Vi. The steric number gives :
   • a) number of bonded atoms
   • b) number of bonded atoms and lone pair of electrons only number of lone pairs vil. Strong reducing agents have
   • a) positive value of standard reduction potential
   • b) greater negative value of standard reduction potential
   • c) lesser positive value of standard reduction potential The indicator employed in the titrations involving the use of iodine solution is
   • b) orange
   • b) -Angle
   • c) Transannular
   • Q.P. Code :03735
   • x. Out of the following, is
   • xi. In chlorobenzene, Cl exhibits effect:
   • a) Only +R effect
   • b) effect
   • xii. is meta directing aromatic electrophilic substitution
   • b) -Cl B State whether the following statements are True or False: 3
   • i. Radio waves have more energy than IR radiations
   • ii. Density of water is less than that of ice
   • iii. Anti-aromatic compounds are more stable than aromatic compounds C Match the following columns: 5
   • i. Mixture of acetic acid & sodium 1)
   • iii. Oxidation state of Mn in Acid buffer
   • iv. Covalency of N 4) Quantisation of energy
5. Q2 A i. The degree of ionization of 0.1 M acetic acid solution is 0.0134 at 298 K. What will be the degree of ionization of 0.05 M acetic acid solution at 298 K 5 marks
   • ii. Explain any three factors that affect degree of ionization. 3 A i. Explain the mechanism of the buffer action of acid buffer. 5 il. Calculate Hydroxyl ion concentration of a solution having pH 4.70 at 298 K 3 B i. Calculate and compare the energies of two radiation, one with wavelength 400 nm and the other 5
   • ii. State and explain law of constancy of interfacial angles 3
   • Q.P. Code :03735 B i. Find Miller indices of the planes whose intercepts on crystallographic axes are 5
   • ii. Write a note on electronic transition C i. Define: b) Common ion effect 2
   • ii. Define: a) electromagnetic spectrum b) of radiation 2 C i. Define: a) Diprotic acid b) Buffer capacity 2
   • ii. Define: a)Axisofsymmetry b) Unit cell 2
6. Q3 A i. Explain (a) covalent bond (b) ionic bond with suitable examples. 4 marks
   • ii. Define polarizability of an anion. Explain any two factors which favour the covalent.character ofan 4 A i. Draw the Lewis dot structure for the following molecules 4 ii)
   • ii. What is VSEPR theory? Describe the basic ideas of VSEPR theory given by Gillespie and Nyholm. 4 B i. Balance the following equation with stepwise explanation in acidic medium: 4
   • ii. The standard electrode potential values of Tl for the following redox reactions are given below: 4 Construct the Latimer diagram and find out the and AG? values for the reaction: B i. Explain the role of as an oxidizing agent with suitable example. 4
   • ii. Calculate the for the titration of 10 cm?of 0.1M Fe(II) versus 0.02M on addition of 4
   • (a) 5.0.cm3(b) 10.0 cm? and (c) 11.0 cm? of 0.02M ina solution of pH = 1 = C the application of VSEPR theory for predicting and F - F bond angles in IF7 [Atomic number of 4 Explain the application of VSEPR theory for predicting shape and F — Xe — F bond angles in XeF2 [Atomic 4 number of Xe
7. Q4 A i. Draw the chair and boat conformations of cyclohexane and explain their relative stabilities. Explain aromaticity of naphthalene. Draw its resonating structures. 3 A i. Explain stability of cyclobutane and cyclopropane on the basis of Angle Strain Theory. 5 5 marks
   • ii. Explain aromaticity of anthracene. Draw its resonating structures. 3 B i. Explain the effect of presence of nitro group on benzene for further electrophilic substitution with 5 respect to orientation and reactivity
   • ii. Explain Huckel’s rule with examples. 3
   • Q.P. Code :03735 B i. How will you prepare cumene from benzene? Name the reaction and write its mechanism. 5
   • ii. Write a note on ortho, para- directing groups in electophilic aromatic substitution. With examples. 3 C i. Which of the following are aromatic: Tropylium cation and cyclopentadiene? Justify your answer
   • ii. Why is cyclobutadiene antiaromatic in nature? 2 C i. What is meant by flipping? Explain flipping in cyclohexane. 4
8. Q5 Attempt any four of the following Derive Henderson equation for the pH of basic buffer. 5 B Distinguish between amorphous solids and crystalline solids. 5 C On the basis of Lewis concept of covalent bonding and double bonding in covalent molecules 5 Find the oxidation number of sulphur in and 5 E What are the conditions which must be satisfied for a compound to exhibit aromatricity? 5 F What is Friedel Craft’s acylation? Give an example with the reaction. 5

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