Mid-Term Exam CHE2103C03 Physical Chemistry-I PDF 2021

THE MAHARAJA SAYAJIRAO UNIVERSITY OF BARODA M.Sc Programme (Semester I) Mid semester Examination Paper: CHE2103C03 (Physical Chemistry-I) Date: 9th January, 2021 (Saturday) Ti...

THE MAHARAJA SAYAJIRAO UNIVERSITY OF BARODA M.Sc Programme (Semester I) Mid semester Examination Paper: CHE2103C03 (Physical Chemistry-I) Date: 9th January, 2021 (Saturday) Time: 11.00-12.00 noon Total marks: 30 Q1 A Multiple Choice question 4 i Which of the following mathematical expression is correct for Maxwell’s distribution of molecular velocity? (where symbols have their usual meaning) 3⁄ 𝑚 2 −𝑚𝑐 2⁄ a) 𝑑𝑛𝑐 = 4𝜋𝑛 (2𝜋𝑘𝑇 ) 𝑒 2𝑘𝑇. dc 1⁄ 𝑚 2 −𝑚𝑐 2⁄ b) 𝑑𝑛𝑐 = 4𝜋𝑛 (2𝜋𝑘𝑇 ) 𝑐 2𝑒 2𝑘𝑇. dc 3⁄ 𝑚 2 −𝑚𝑐 2⁄ c) 𝑑𝑛𝑐 = 4𝜋𝑛 (2𝑘𝑇 ) 𝑐 2𝑒 𝑘𝑇. dc 3⁄ 𝑚 2 ⁄2𝑘𝑇 −𝑚𝑐 2 d) 𝑑𝑛𝑐 = 4𝜋𝑛 (2𝜋𝑘𝑇 ) 𝑐 2 𝑒. dc ii Which of the following assumption is FALSE for Maxwell’s distribution of molecular velocity? a) The number of molecules present per unit volume at any point is same. b) The distribution of velocity equally apply to the smallest element of the volume c) The total number of molecules possessing a given velocity is not constant. d) None of the above iii Most probable velocity: average velocity: root mean square velocity have the following ratios of their values a) 1: 1.128: 1.224 b) 1.128: 1: 1.224 c) 1.224: 1.128: 1 d) 1: 1.224: 1.128 iv The temperature at which the average velocity of oxygen equal that of hydrogen at 20 K is ……….. a) 160 K b) 640 K c) 320 K d) 80 K B Calculate the Z11 (Homonuclear) collision for N2 at 27°C and 1 atm 3 pressure.  C Define Mean free path. Derive the relationship between mean free path 3 of a gaseous molecule and temperature and pressure. Q2 A Multiple choice questions 4 i) An example of complex reaction is a) Hydrolysis of ester b) Inversion of sucrose c) Radioactive decay d) Saponification of ester ii) For the chain reaction H2 (g) + Br2 (g) →HBr, the rate law for the formation of HBr is a) d[HBr]/ dt = k [H2] [Br2] b) d[HBr]/ dt = k [H2]1/2 [Br2] c) d[HBr]/ dt = k [H2] [Br2]1/2 d) d[HBr]/ dt = k [H2]1/2 [Br2]1/2 iii) In the kinetics of branched chain reaction, if the number of chain carriers in the propagation step is more than one, then a) Stationary chain reaction occurs b) Equilibrium reaction occurs c) Isothermal explosions take place d) None of the above iv) In a reversible reaction, the following expression is for 𝑥𝑒 𝑥𝑒 ln ( ) 𝑎𝑡 𝑥𝑒 − 𝑥 (where symbols have their usual meaning) a) Forward rate constant b) Backward rate constant c) Equilibrium constant d) None of the above B Derive the expression for most probable velocity of gases using 2 Maxwell’s distribution of molecular velocity. C For the dissociation of water, the relaxation time obtained from the 4 temperature jump method is 36 μs at 25°C. Calculate k1 and k-2. Q3 A True or False. [T/F] 4 i) Micelle formation always takes place with decrease in entropy. [ ] ii) At CMC, the conductance of a surfactant solution increases. [ ] iii) Generally, in molecular structure of surfactant, the long chain hydrocarbon part is polar and ionic part is non-polar. [ ] iv) The micellar solution is heterogeneous in nature. [ ] B Discuss classification of surfactants with few examples. 3 C Discuss Packing parameters in brief. 3 ********