CSIR NET Chemical Science: Most Important Questions of Physical Chemistry!!! (Download PDF)

Physical Chemistry - Most Important Questions

1. What is the percentage hydrolysis of aniline acetate in a decimolar solution if the dissociation constants of aniline, acetic acid and water at 25ºC are, respectively, 3.83 × 10^–10, 1.75 × 10^–5 and 1.008 × 10^–14
   A.50.95
   B.54.95
   C.62.78
   D.60.00
2. Calculate the number-average (gmol^-1) and mass-average mass(kg mol¹) respectively for a protein sample which consists of an equimolar mixture of haemoglobin (M = 15.5 kg mol^–1), ribonuclease (M = 13.7 kg mol^–1) and myoglobin (M = 17.2 kg mol^–1).
   A.15500 and 15.6
   B.16540 and 19.6
   C.189650 and 13.4
   D.15350 and 18.5
3. If molar conductances at infinite dilution of AgNO₃, HNO₃ and HCl are, respectively, 133.0 × 10^–4, 421.0 × 10^–4 and 426.0 × 10^–4 S m² mol^–1, calculate the solubility of AgCl in grams per dm³ in water at the given temperature if the specific conductance of a saturated solution of AgCl is 2.68 × 10^–4 S m^–1 and that of water with which the solution was made is 0.86 × 10^–4 S m^–1.
   A. 1.45 × 10–3 g dm^–3
   B. 3.89 × 10–3 g dm^–3
   C. 2.12 × 10–3 g dm^–3
   D. 1.89 × 10–3 g dm^–3
4. The density of LiF is 2.601 g cm^–3. The (111) first-order reflection in the X-ray diffraction from LiF occurs at 8º44' when X-rays of wavelength 70.8 pm are used. Calculate Avogadro's number if there are four LiF molecules per unit cell. LiF crystallizes in the cubic system. Li = 6.939, F = 18.998
   A. 6.89 × 1023 mol^–1
   B. 6.01 × 1023 mol^–1
   C. 6.49 × 1023 mol^–1
   D. 5.59 × 1023 mol^–1
5. A radiation of wave length 2500 A was passed through a cell containing 10 ml of a solutions which was 0.05 molar in oxalic acid and 0.01 molar in uranyl sulphate. When 80 joules of radiation energy is absorbed, the concentration of oxalic acid was reduced to 0.04 molar. Calculate the quantum yield for the photochemical decomposition of oxalic acid at the given wave length.
   A. 0.60
   B. 0.45
   C. 0.30
   D. 0.34
6. What will be the entropy change for the freezing of one mole of water of 25ºC to ice at –10ºC; given that the heat of fusion of ice at its fusion point (0ºC) is 6.00 kJ mol¹, the heat capacity of ice is 36.82 J K^–1 mol^–1 and heat capacity of liquid water is 75.31 J K^–1 mol^–1.
   A. -30.57 J K^–1 mol^–1.
   B. -29.96 J K^–1 mol^–1.
   C. -21.23 J K^–1 mol^–1.
   D. 13.95 J K^–1 mol^–1.
7. The pure rotational (microwave) spectrum of gaseous HCl consists of series of equally spaced lines separated by 20.80 cm^–1. Calculate the internuclear distance(pm) of the molecule if the atomic masses are: 1H = 1.673 × 10^–27 kg : 35Cl = 58.06 × 10^–27 kg.
   A.140
   B.139
   C.129
   D.110
8. The fundamental vibrational frequency of HCl is 2,890 cm^–1. Calculate the force constant (Nm^–1) of this molecule if the atomic masses are 1H = 1.673 × 10^–27 kg; 35Cl = 58.06 × 10^–27 kg.
   A.483
   B.576
   C.223
   D.456
9. The force constant of H₂ is 510 N m^–1 and its dissociation energy is 4.5 V.What will be the vibrational quantum number corresponding to its dissociation energy assuming it vibrates as a simple harmonic oscillator.
   A.2
   B.4
   C.8
   D.5
10. What will be the enthalpy when water is supercooled to –4ºC?
    A. less than ice at –4ºC
    B. more than ice at –4ºC
    C. same as ice at 0ºC
    D. same as ice at –4ºC

Solutions

           10. When ice is supercooled to –4ºC, heat will be released, so enthalpy decreases.

Answer keys:

1. B
2. A
3. D
4. C
5. A
6. B
7. C
8. A
9. C
10. A

Check Out: 

• Study Notes for CSIR NET Life Science - BIOCHEMISTRY (Download PDF)
   
• Study Notes for CSIR NET Chemical Science - Download PDF Here!
   

→ If you have any questions feel free to ask in the comments section below.

Best of Luck!!
Sahi Prep hai to Life Set Hai!!
Go BYJU'S Exam Prep