B.E UNIVERSITY EXAMINATION Question paper - ENGINEERING CHEMISTRY

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B.E.DEGREE EXAMINATION

FIRST YEAR

ENGINEERING CHEMISTRY

Answer all the questions

Part-A=10*2=20

1.Name any one coagulant used to remove the turbidity of the water?

2.Why should natural water should not be fed to boiler?

3.Why do electrochemical cells stop working after sometime?

4.Why is the salt bridge used in the construction of the cell?

5.What is soft abrasive?Give some examples for synthetic abrasive.

6.Name any four solid lubricants?

7.Solid surfaces are capable of adsorbing solutes from solutions-Explain with example

8.Define Degree of Freedom?

9.Distinguish between gross and net calorific value of fuel

10.What is meant by octane number of a gasoline?

PART-B(5*12=60)

11.a)What is the principle of EDTA titration?Briefly describe the estimation of hardness of water by EDTA method.What is the role of buffer in EDTA titration?

OR

b.)What is the break point chlorination . Write a note on disinfection by chlorine.

12.a)Differentiate between chemical and electro chemical corrosion? Write short notes on special paints?

OR

b.)Bring out the similarities and dissimilarities in electro plating and anodizing techniques.Give explanation of the two.

Explain differential aeration corrosion with example

13.a)What are refactories? What are the prime requsite of a material to be used as refactory related to its porosity?

OR

b.)What are the functions of the filters and plasticizers in plastic industry?

With neat diagram explain injection molding

14.a)Discuss the Langmuirs theory of adsorption and derive expression for mono layer Langmuir adsorption isotherm

OR

b.)Discuss the effect of increasing carbon content in steel .What is meant by annealing of steel?

15.a)Define flue gas.How the analysis of gas is done by Orsat's apparatus?What conclusion can be drawn from the experiment ?What is the significance of the analysis?

OR

b.)Explain briefly the principle in flame photometric analysis and give the block diagram of instrumentation.

[ganeshbala]

2008 Jawaharlal Nehru Technological University B.Tech Mechanical Engineering engineering chemistry Question paper

B.Tech Supplimentary Examinations, Aug/Sep 2008


ENGINEERING CHEMISTRY

( Common to Mechanical Engineering, Mechatronics, Production Engineering and Automobile Engineering)

Time: 3 hours Max Marks: 80
Answer any FIVE Questions
1. (a) What is meant by sterilization of water? Expalin how sterilization of water is carried out by using chlorine and ozone.
(b) 0.28 g of CaCO3 was dissolved in dil.HCl and the solution made up to one litre with distilled water. 100 mL of the above solution required 28 mL of
EDTA solution for titration. 100 mL of the water sample required 33 mL of same EDTA solution for titration. After boiling 100 mL of this water, cooling,
filtering and then titration required 10 mL of EDTA solution. Calculate the temporary and permanent hardness of water. [9+7]

2. Write short notes on :
(a) Priming and Foaming
(b) Phosphate conditioning
(c) Caustic embrittlement. [5+6+5]

3. (a) Describe how electrochemical properties are used in protecting submerged
metals from being corroded.
(b) Explain the corrosion of iron by dilute mineral acids. [8+8]

4. (a) List the differences between anodic coating and cathodic coating.
(b) How zinc coated on iron prevents corrosion?
(c) Explain sand blasting method of surface preparation. [8+4+4]

5. (a) Explain the process of Extrusion moulding with a neat diagram?
(b) How are the following polymers prepared? Mention their properties and uses.
i. PVC
ii. LDPE. [6+10]

6. (a) Define Refractories and what are the criteria of a good refractory?
(b) Give the clasification of refractories with suitable examples. [6+10]

7. (a) Explain how the following act as lubricants:
i. Graphite
ii. Molybdenum disulphide.
(b) How does pour-point depressant function as an additive in blended oils?[12+4]

8. (a) What is metallurgical coke? How it is superior than coal? Explain the manu-
facture of metallurgical coke by Otto Hoffman’s by product coke oven method.
List the various by products obtained.
(b) Define octane number of gasoline. Why is ethylene di bromide added, when
tetra ethyl lead is used as an antiknock? [10+6]

[ganeshbala]

I B.Tech Supplimentary Examinations, Aug/Sep 2008

ENGINEERING CHEMISTRY

( Common to Mechanical Engineering, Mechatronics, Production Engineering and Automobile Engineering)
Time: 3 hours Max Marks: 80

Answer any FIVE Questions

1. Write short notes on the following :
(a) Break-point chlorination
(b) Slow sand filtration
(c) Impurities in water and their effects. [5+5+6]

2. Write short notes on :
(a) Priming and Foaming
(b) Phosphate conditioning
(c) Caustic embrittlement. [5+6+5]

3. (a) What is electrochemical corrosion and how does it occur? Describe its mech-
anism.
(b) What are corrosion inhibitors? Discuss anodic and cathodic inhibitors with
suitable examples. [8+8]

4. (a) What are the functions of a thinner in a paint?
(b) What are organic coatings? Mention the factors on which they depend ?
(c) Mention the function of antiskining agent which is added to paint. Give ex-
amples. [6+6+4]

5. Write the structure of four addition polymers and 4 condensation polymers with
their respective monomers. [16]

6. (a) What is pyrometric cone equivalent? How it is determined for a refractory?
What is its significance?
(b) Write a short note on:
i. porosity
ii. Thermal Conductivity
iii. Dimensional Stability
iv. strength. [8+8]

7. (a) Give the functions of lubricants.
(b) Describe the mechanism of extreme pressure lubrication.
(c) How a viscous lubricant is converted into grease? [6+6+4]

8. (a) Explain how fuels are classified with suitable examples.
(b) Explain the significance of the following constituents present in coal.
i. Moisture
ii. Volatile matter
iii. Ash and
iv. Fixed carbon. [8+8]

I B.Tech Supplimentary Examinations, Aug/Sep 2008

ENGINEERING CHEMISTRY

( Common to Mechanical Engineering, Mechatronics, Production Engineering and Automobile Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks

1. Write a short note on the following:
(a) Ozonization
(b) Caustic embrittlement.
(c) Zeolite softeners. [4+6+6]

2. Write short notes on :
(a) Priming and Foaming
(b) Phosphate conditioning
(c) Caustic embrittlement. [5+6+5]

3. Write short note on the following:
(a) Concentration cell corrosion with an examples
(b) Conditions for wet corrosion to occur
(c) Units of the rate of corrosion. [10+3+3]

4. Briefly discuss the various metallic coatings that prevent corrosion. [16]
5. (a) Explain the process of Extrusion moulding with a neat diagram?
(b) How are the following polymers prepared? Mention their properties and uses.
i. PVC
ii. LDPE. [6+10]

6. (a) Define Refractories and what are the criteria of a good refractory?
(b) Give the clasification of refractories with suitable examples. [6+10]

7. (a) Distinguish between hydrodynamic lubrication and boundary lubrication.
(b) Distinguish between hydrodynamic lubrication and extreme pressure lubrica-
tion. [8+8]

8. (a) Explain Junker’s gas calorimeter for the determination of calorific value of a
gaseous fuel?

(b) Distinguish between the followings.
i. Gross and net calorific values
ii. Octane number and cetane number. [10+6]