Chemical Energetics, Ionic Equilibria and Nanomaterials — DU B.Sc. (Hons) Biological Sciences Previous Year Question Papers

(a) State the advantages of using Scanning Electron Microscopy. (SEM) • (b) Discuss the application of nanomaterials in drug delivery. Differentiate between bond dissociation energy and bond energy taking a suitable example. Explain the ionic product of water. How does it vary with temperature. (e) Illustra,te the ffaree applications of solubility product principle. cO How are nanomaterials different from their bulk materials? 5x3 (c[) What distinctions exist between the methods used to characterize nanoparticles using TEM and SEM techniques ? Which one, and why, is more suited for determining the` size and shape of nanoparticles ? (a) A monobasic acid has a dissociation constant equal to 1.8 x 10-5 at (a) 25°C. 'Calculate i-ts degree of dissociation at .a concentration of 0.2 M at the same temperature. Draw Born-Haber cycle for Licl system for calculat`ing the lattice energy. (d) Define the following : (cb) (a) (i) Enthalpy of formation (I.i) Enthalpy-of neutralization. 4,4,4,3- What i.'s.buffer capacity? Exblain the 'bu`ffer action of a.basic buffer. Calculate the solubility in- grams per litre of. Al(OH)3 in water at (c) Describe carbon nanotubes and their applications with respect to biosensors. (d) What are Quantum dots (QD) ? Compare the band energies for a quantum dot nanocrystal and a bulk semiconductor. 4,4,4,3 (a) Which properties make nanomaterials suitable for catalytic applications ? (b) Explain the difference between the top-down and bottom-up approach. for the fabrication of nanomaterials giving one example of each. (c) Describe how Infrared (IR) spectroscopy helps in characterizing the nanoparticles by giving an example. (d) The pH of pure water at 50°C is less than 7. Justify. 4,4,4,3 (a) Derive the relation between the pH of the solution and the relative amounts of the acid and salt present in it. (b) Explain in detail how XRD analysis is important in nanomaterial characterisation. (c) Describe in brief one method of synthesis of silver nanoparticles. (d) The heat of neutralization of a strong acid with a strong base is -57.36 kJ mol 1. If the heat of neutralization of a weak acid HA with a strong base be -42.02 kJ mol1, then compute the heat of ionization of weak acid. 4,4,4,3 (a) Derive the following expressions for a salt of strong acid and weak base: (b) Explain the effect of temperature on pH. - (c) Write short notes on any two : (i) Green method of synthesis of nanomaterials