1. Answer the following questions: 2×10 Show that ∂G for any phase change transition is always Zero. Ans: We know ∂G = V∂P – S∂T. A phase change transition occurs at constant temperature and pressure, i.e. ∂P = 0 = ∂T ∂G = 0. (b) What are the conditions that wave function must satisfy? Ans: A wave function must be i. Finite, continuous & single valued. ii. Differentials of ψ must be continuous functions of x, y & z respectively. iii. ψ must be a normalized wave function. (c) What do you mean by Eutectic temperature and Critical temperature? Ans: Eutectic Temperature: It is the temperature at which an easy melting intimate mixture (a solid solution) known as eutectic mixture is formed. Critical Temperature: It is the temperature that corresponds to critical point, which is the end point of a phase equilibrium curve. (d) Calculate Free energy change when 5 mole of oxygen at 300K and 5 bar pressure expand isothermally to 1 bar pressure. Ans: Given, n = 5, T = 300K, P1= 5 bar & P2= 1 bar. . (a) (e) (f) How much heat evolved when 266gmof white P4 burn in air? Ans: The combustion equation for P4 can be written as P4 + 5O2 → P4O10, Let ΔH be the heat of combustion. No. of moles (n) in 266 gm = (266/ molecular mass of P4) = (266/31×4) = 2.145. The amount of heat evolved when 266gmof white P4 burn in air= 2.145× ΔH J. Write down cell reaction of Dry cell and Fuel cell. Ans: Dry Cell At anode: Zn (s) → Zn2+ + 2eAt cathode: 2MnO2+ Zn2+ + 2NH4+ + 2e-→ Mn2O3+ H2O+ Zn(NH3)2]2+ Net cell reaction: 2MnO2 + Zn + 2NH4+ + 2e- → Mn2O3+ H2O+ Zn(NH3)2]2+. Fuel Cell( e.g H2-O2 fuel cell) At anode: At cathode: H2 2H+ + 2OH- 2H2O H2 + 2OH- 2H2O + 2e- O2 + 2H2O + 4e- Net reaction is 2H2 + O2 (g) 2H+ + 2e- 4OH2H2O If K<1then what is the condition of reactant and product at equilibrium? Ans: Let A ⇌ B, is a reaction at equilibrium. [ ] The equilibrium constant, . If K<1, than [B] < [A] i.e the concentration of product is [ ] less than that of the reactant. (h) What do you mean by enzyme catalyst? Give an example of enzyme catalytic reaction. Ans: Enzymes are high molecular weight complex organic substances and are capable of catalyzing reactions in living cells and the phenomenon is known as enzyme catalysis. Example: C12H22O11 + H2O → 2C6H12O6, Here Maltase is used as the catalyst.