Shri R. L. T. College of Science, Akola Department of Chemistry, Question Bank B. Sc-II (Semester-IV) Paper: 4S Chemistry Physical Chemistry (Unit-V & VI)
Short Answer Question (1 Mark) 1.What is the molal elevation constant? Give its unit. 2.What is ebullioscopic constant? 3.What is cryoscopic constant? 4.What is Van’t Hoff Factor? 5.What is colligative property? Name the four colligative properties? 6.What is elevation of boiling point? 7.What is depression of freezing point? 8.What is Axis of Symmetry? 9.What is Low of Symmetry? 10. What is unit Cell? 11. Define the Following terms (1 M each) 12. i) Unit cell ii) Space lattice iii) Plane of Symmetry iv) Point of symmetry v) Weiss indices vi) Center of symmetry vii) Lattice point viii) Axis of symmetry ix) Simple cubic crystal x) Body centered cubic xi) Face centered cubic 13. Define the Following terms (1 M each) i) Dilute solution ii) Boiling Point, iii) Freezing Point, iv) Van’t Hoff Factor, v) Molal Elevation constant, vi) Molal depression constant vii) Solution viii) Solvent
Fill in the Blanks (1/2 Mark Each) i) Phenol in chloroform to form double molecule. ii) The elevation in boiling point is proportional to pressure. iii) Van’t Hoff factor for sucrose is . iv) The property which depends on the number of particals of the substance in solution is known as property. v) The presence of solute the boiling point of solvent. vi) The presence of solute the freezing point of solvent vii) What is Beckmann thermometer is a thermometer. viii) Crystals cab be classified into system ix) Bragg’s equation for the diffraction of X-ray by crystal is . x) Crystals have faces and edges
xi) is the branch of science which deals with the study of geometry, properties and structure of crystal and crystalline substance. xii) is the set of lattice point arranged at equal distance along straight line. xiii) Unit cell of NaCl contain molecule of NaCl. xiv) Amorphous solid considered as liquids. xv) Crystalline solid also called as solid.
Choose the correct alternative (1/2 Mark Each) xvi) The miller indices for Weiss indices 1:2:3 are a) 312 b) 321 c) 632 d)123 xvii) i) The total number of atoms per unit cell in face centered cubic (fcc) lattice a) 1 b) 3 c) 2 d) 4 xviii) The number of atoms per unit cell in body centered cubic (bcc) lattice a) 1 b) 3 c) 2 d) 4 xix) Which of the following is not a colligative Property a) Elevation of Boiling Point b) Boiling Point c) Depression of Freezing Point d) Osmotic pressure xix) Molal depression constant of Camphor is a) Kf=37.7 Kgmol-1 b) Kf=14.40 Kgmol-1 c) Kf=6.90 Kgmol-1 d) Kf=20.0 Kgmol-1
Long Answer Question (4 to 6 Marks) 1. Differentiate between crystalline and amorphous solid? 2. Derive Bragg’s equation for diffraction of X-axis by crystals? 3. Show the unit cell of NaCl contains four molecule of NaCl? 4. Describe the Bragg’s spectrometer method for determination of crystal structure? 5. On the basis of thermodynamic consideration Derive equation for molal elevation constant? 6. How will you derive a relation between elevation of boiling point and molal mass of solute thermodynamically? 7. Describe Cottrell’s method for determination of elevation of boiling point? 8. State and explain Van’t Hoff factor? 9. Derive equation of Van’t Hoff factor when the solute undergo association? 10. A solution of sucrose (Molar mass=342Kgmol-1) is prepared by dissolving 68.4X10-3Kg in 1 Kg of water. Kf for water is 1.86K Kg Mol-1. Find the freezing point of the solution. (272.62K) 11. Derive an equation for molal depression constant on the basis of thermodynamic consideration.
12. On the basis of thermodynamics point of view, derive a relation between depression of freezing point and molecular weight of solute? 13. Describe Rast’s method of determine depressing of freezing point and molecular weight of solute? 14. Why do some substances (Electolytes, for eg.) show abnormal colligative properties? Explain 15. What are the reasons for abnormal behavior of solutions? 16. How Degree of association of solute is determined? 17. Derive equation of Van’t Hoff factor when the NaCl is dissolved in water. 18. Acetic acid associates in benzene to form dimer. 1.65X10-3 Kg. of acetic acid whem dissolved in 0.1Kg of benzene, raised the boiling point by 0.36K. Calculate Van’t Hoff factor and degree of association of acetic acid in benzene.Kb for benzene is 2.57K Kg mol-1 (i= 0509 and α=0.982 ) 19. Calculate the boiling point of solution containg 0.018 kg glucose in 0.1kg of water Kv for water is 0.52Kkgmol-1 ().520C) 20. The boiling point of solution of 0.105 kg of substance in 15.84kg of ether was found to be 0.100 K higher that of pure ether calculate the molar mass of the substance.Kb for ether =2.16KkgMol-1(143.2.kgmol-1) 21. Define different element of symmetry in cubic crystal? 22. Explain the structure of KCl on the basis of X-ray diffraction? 23. Determine the number of constituent’s particles in the face centered cubic unit cell? 24. Why KCl behave like scc towards X-ray? 25. The length side of unit cell of a cubic crystal is 4X10-8m. The density of crystal is 1.2X10-3Kg m-3. If the molar mass is 24X10-3Kg mol-1 find out i) number of atoms in each unit cell ii) type of lattice (No=6.023 X 1023) 26. The first order reflection maxima was noted 5.9o from 100 planes of scc calculate wavelength of X-ray if interplaner spacing was 0.282 mm 27. The length of edge of cubic lattice in 205 A0 calculate the interplaner distance for its (231) planes. 28. Calculate glancing angle of first order reflaction from 100 planes of fcc if x-rays of wavelength of 0.154nm are used (given spacing of 100 plane is 0.315nm) 29. Find out miller indices of Weiss indices of a) 2:4:3 b) 1:ᴽ ¼ 30. Explain the Bragg’s Equation and experimental method to study the structure of crystal.