KTU Model Question paper - Chemistry

KTU-Scheme Question Paper Engineering Chemistry (CY100) 

Part A. Answer all questions. Each question carries 2 marks.

1.       What property of nuclei is involved in NMR spectroscopy? Give two examples of each type.

2.       What is the voltage generated by the H₂--O₂ fuel cell operating under standard condition? A fuel cell is considered better than an electrical power plant using the same fuel. Why?

Ans   1.23 V.  In fuel cell the reactions are taking place in nearly reversible manner, therefore more useful work can be obtained. In an electric power plant the fuel + oxidant reaction is taking place in a non reversible manner, so efficiency will be relatively low.

3.       Give two examples of carrier gases used in GC analysis? Why oxygen is not suitable carrier has for GC analysis?

4.       How silicone rubber is obtained from silicones? Give the reaction.

5.       Define lubricant and lubrication. What are the functions of lubricants?

6.       Give the condition when the GCV and NCV will be same?

7.       What are the different units used to express degree of hardness?  Give their inter relationship. (3)

8.       Comment on the statement “hardwater is not a health risk but is a nuisance”

Part B. Answer all questions. Each question carries 3 marks.

9. Explain how you could use IR spectroscopy to distinguish compound I and II? (Hint not based on C-F stretching)

10. A zinc rod is dipped in 0.1M solution of ZnSO₄. The salt is 95% dissociated at 298K. Calculate the electrode potential.

11. In what way DTA study of polymers helpful to a researcher?

12. Differentiate between SWCNT and MWCNT ?

13. How do graphite and molybdenum sulphide function as lubricants? Explain.

14. Compare LNG Vs CNG.

15. Why CaCO₃ is used as standard for expressing degree of hardness? (3)

16. Calculate the hardness of 0.01 M and 0.01 N AlCl₃ each solution separately.      

Part C. Answer any one full question (10 * 1 = 10 marks)

Module I

17. a. Arange in the increasing order of wave number of the stretching vibrations of           (1) C-H (alkane), (2) O-H (alcohol), (3) C=O (ketone), and (4) C≡C (alkyne)? (2)

       b. When a monochromatic light of 480 nm is passed through a dye solution of thickness 2 cm transmits 40% incident light. Calculate the concentration of dye solution, given that molar absorption coefficient recorded is 6000 dm³mol^-1cm^-1. (3)

       c.  Give examples of two applications of each IR, UV/Visible. (2)

       d. Give a brief account on Free induction decay in MRI scanning.  (3)

            Ans.   In a magnetic field, the nuclear energy levels of Hydrogen splits.   

            
   An RF signal corresponding to DE is given then the nucleus flips to the other possible orientation.

                At a later time after excitation, spins slowly return to the initial state of equilibrium. The energy is reradiated. This reradiated energy is observed as an MRI signal (called Free Induction Decay FID signal) and is processed to construct the image with the help of computer.

Or

18. a. Which one out of 1,3-pentadiene and 1,4-pentadiene will have longer wavelength of absorption maximum .  Explain (3)

      b. Distinguish between absorption and emission spectroscopy . (2)

      c. Why TMS is used as a reference in ¹H-NMR spectrum of organic molecule? (2)

           Ans. Silicon is more electropositive than Carbon. Therefore the 12 identical protons in TMS are highly shielded and we get signal at high field strength. Chemical shift is expressed relative to TMS. For all organic molecules the signal for proton will fall in the left side of TMS.

      d. Draw a neat schematic diagram of an NMR instrument. (3)

           

Module II

19. a. What is electrochemical series? Give any four applications. (4)

       b. What are reversible and irreversible cell. Give examples (4)

           Ans A cell is said to be reversible if the following two conditions are fulfilled

(i) The chemical reaction of the cell stops when an exactly equal external emf is applied.

(ii) The chemical reaction of the cell is reversed and the current flows in opposite direction when the external emf is slightly higher than that of the cell. Any other cell, which does not obey the above two conditions, is termed as irreversible.

Daniell cell is reversible but Zinc-Silver cell is irreversible in nature

       c. Explain why dilute hydrochloric acid cannot be used for the acidification during the redox titration using KMnO₄? (2)

            Ans. KMnO4 is a strong oxidizing agent. It will oxidise Cl^- in HCl to ½ Cl₂ gas. Thus error will introduce in the redox titration.

Or

20. a. Explain the construction and working of Hydrogen electrode. Mention its limitations. (3)

      b. Write a note on Helmholtz electrical double layer. (3)

      c. Write the differences between primary and secondary cells? Give examples. (2)

      d. Devise an experiment to measure the standard electrode potential of Cu/Cu²⁺ electrode. (2)

Module III

19. a. Write short note on TLC. (4)

       b. Calculate the conductivity of given sodium chloride solution at 298 K which shows a conductance of 500 micro-mho in a cell. A standard solution of 0.01 M KCl shows a conductance of 128 micro-mho in that cell. Given that conductivity of 0.01 M KCl solution is 0.00128/(ohm cm) at 298 K. (4)

       c. What is the necessity of guard column in HPLC? (2)

Or

20. a. What is the use of a pre-heater in GC instrument?(2)

      b. Based on the mechanism of separation, classify chromatographic technique. (2)

      c. Write down the application of conductivity measurement. (2)

         Ans: Conductivity measurements are used to monitor quality of public water supplies, Ionic concentrations, Salinity, Sodium Concentrations in Urine

      d. With the help of a neat block diagram explain the working of TGA and how is it different from DTA? (4)

     

Module IV

21. a. Describe the preparation and uses of any two commercial important synthetic elastomers. (4)

       b. What is nano material? Explain the synthesis of nano material by solgel method. (4)

       c. Discuss any four applications of conducting polymers. (2)

Or

22. a. What are conducting polymers? Show that how doping can improve its conductivity. (5)

       b. Explain addition and condensation polymerization with suitable examples? (5)

  

Module V

23. a. A bomb calorimeter containing 900 grams of water was calibrated by burning a sample of benzoic acid (C6H5COOH), its HCV is 2700.00 Cal/kg. When 1g of benzoic acid is burned in the calorimeter, the temperature of the water and the calorimeter increases by 3°C. Using these data, calculate the calorimeter constant. (5)

       b. Describe the determination of Flash and fire point using Penskey Martins Apparatus. (5)

      

Or

24. a. What are the different types of lubricants? Give details. (3)

       b. Define viscosity index. How it is determined? (4)

       c.  Write the detailed calculations involved in the determination of calorific value of a solid fuel by Bomb-calorimeter. (3)

Module VI

23. a. Calculate the hardness of water sample, whose 10 ml require 20 ml of EDTA solution. 20 mL of standard hard water which contains 1.5 g of  CaCO₃ / L require 30 ml of EDTA. (5)

       b.  Calculate the hardness of given sample of water, if 50 ml of sample water gives endpoint with 20 ml of EDTA solution. 20 ml of standard hard water of concentration 0.02 M gives end point with 25 ml of EDTA solution. (5)

   

Or

24. a. Calculate the temporary, permanent and total hardness of water in ppm having the following composition.  Ca(HCO₃)₂ = 4ppm, Ca(HCO₃)₂ = 6 ppm, CaSO₄ = 8ppm, MgSO₄ = 10 ppm and NaHCO₃ = 3 ppm?. (5)

       b. Explain with a sketch, the various steps involved in the treatment of water for domestic purpose. (5)