General Instructions:
(i) The question paper is divided into 4 Sections – A, B, C and D
(ii) All questions are compulsory
(iii) This question paper contains 1 printed page.
(iv) Section A, consist of 5 Questions (1-5) of 1 mark each.
(v) Section B, consist of 3 Questions (6-8) Of 2 marks each.
(vi) Section C, consist of 3 Questions (9-11) of 3 marks each.
(vii) Section D, consist of 1 Question of 5 marks.
Section-A
- How are 0.50 mol NaCl and 0.50 M NaCl different?
- How many significant figures are present in 0.002500?
- What is the value of first Bohr radius?
- Why is the energy of electron regarded as zero?
- Define Law of multiple proportion.
Section-B
6. The density of 3 molal solution of NaOH is 1.110 g/ml, calculate the molarity of the solution.
7. Calculate the wavelength of an electron moving with a velocity of 2.05×107 m/s. [Mass of electron is 9.1×10-31kg, h=6.626×10-34kgm2/s]
8. How many electrons in an atom may have the following quantum numbers?
n= 4; 1=3 b) n= 3; 1=2
Section-C
9. Calculate the molarity & molality of 93% (w/v) of H2SO4. The density of the solution is 1.84g/ml. [At mass of H = 1u,S=32u and O=16u]
10. Write Short notes on i) Hydrogen spectra ii) Photoelectric effect.
11. Calculate the wavelength for the longest wavelength transition in the Balmer series of atomic hydrogen. ( R= 109677cm ฬ 1)
Section-D
12. a) Define mole fraction of a solution.
b) Molarity of H2SO4 is 0.8 M and its density is 1.06g cm3. What will be the concentration of the solution in terms of molality and mole fraction?
OR
12. a) Define molarity and molality of a solution.
b) A compound containing C, H and O gave the following analytical data: C = 40.0%, H = 6.67% and rest oxygen. Calculate the molecular formula of the compound if its molecular weight is 180.
