B. Sc. (VI Semester) Examination
CHEMISTRY
Paper: CHEM-361
(Physical Chemistry)
Full Marks : 80
Pass Marks : 35%
Time : Three Hours
Note: (i) Answer all the questions.
(ii) The figures in the margin indicate full marks for the questions.
(iii) The symbols used are of usual meaning.
1. Answer all questions: 2x5 = 10
(a) Write the equitation for Langmuir absorption isotherm under high pressure.
(b) How many moles of helium are produced when one mole of 92U238 disintegrates into 82Pb206?
(c) What is condensation polymerization?
(d) Calculate the wavelength of a Co2 molecule moving with a velocity of 440 m/sec.
(e) What is rotational constant?
2. Answer any four questions: 5x4= 20
(a) Define coagulation of colloids. The coagulation of 100 ml of arsenious sulphide solution. 5 ml of 1 M NaCl is required calculate the coagulating power of NaCl. 1+4= 5
(b) The half life period of radioactive element is 1590 years. In how many years will one gram of pure element (a) lose one centigram and (b) be reduced to one centigram? 2+3= 5
(c) A polymer consists of 40% by weight of macromolecule of molecular weight 10000 and 60% by weight of macromolecule of molecular weight 75000. Calculate the M-n and M-w of macromolecule. 5
(d) What do you mean by normalization? Normalize the wave function
(e) Discuss the factors affecting width and intensity of spectral lines. 5
3. Answer any five questions: 10x5= 50
(a) (i) What are the differences between chemical and physical absorption? 6
(ii) The coagulation of 100 ml of a colloidal solution of gold is completely prevented by adding 0.25 g of starch to it before adding 10 ml of 10% NaCl solution. Find out the gold number of starch. 4
(b) (i) What is radioactive disintegration? Define half life and average life of radioactive substance. 5
(ii) Discuss the meson theory of nuclear forces. 5
(c) (i) What are the postulates of quantum mechanism? 4
(ii) Show that the wave function
Where, l ≠ m are orthogonal wave functions. 6
(d) What do you mean by rigid rotator? Discuss the spectra of diatomic molecule and derive expression for rotational energy. 10
(e) (i) How molecular weight of macromolecules is determined by osmotic pressure method. 5
(ii) Discuss the mechanism of free-radical polymerization. 5
(f) Write short notes on any two of the following: 5x2= 10
(i) Separation of Isotopes
(ii) Applications of radio activity
(iii) Particle in one-dimensional box
