Sunday 11 November 2012

ENGINEERING CHEMISTRY-II


Note : Attempt all questions . part (a) of each question is compulsory and attempt any two parts from remaining question
UNIT-I
Q1 (i) For estimation of alkalinity in a water sample phenolphthalein and methyl orange end points were found to be 30ml and 45 ml respectively.
The readings indicate the presence of:
(a) OH and Co3         (b) Co3 and HCo3
(c) OH and HCo3         (d) Only HCo3
 (ii) Temporary hardness in water is due to:
(a) MgSo4n                (b) CaCo3
(c) Na2So4                 (d) Ca (NOa3)2
(B) (i) 500 ml of water sample contains 0.296 gm of Mg (No3)2- Calculate the hardness of the water sample  in degree Clark.
(ii) A water sample was softened. by hot lime soda process. The analysis of softened water gave  the following data :
OH 34ppm        COa 90ppm.
Calculate the amount of lime and soda used in excess of the theoretical amount for the treatment   of 1000 liters of the
water   sample.
(C) (i) Give the limitations of the zeolite process for softening hard water.
(ii) The hardness of 10,000 liters of a hard water sample was completely removed by passing it through
a zeolite softener. The softener then required 40 liters of NaCI solution containing 125gms/1
Of NaCI for regeneration. Calculate the hardness of the water sample in ppm.
(D) (i) Explain the role of coagulant in water treatment,
(ii) Write a short note on “Break** point chlorination*.
UNIT-II
Q2(A)  (i) Calorific value of carbon is :
(a) 2240 calories per gm.    (b) 34500 calories per gm
(c) 96.96 kcal per mole       (d) 8080 kcai per mole
(ii) A gasoline sample has the same knocking characteristics as the mixture containing 80%
isooctane  and 20% n-hepianes. The octane number of gasoline must be :
(a) 0                                 (b) 20
(c) 100                          (d) 80
(B)  Draw a well labeled diagram of bomb calorimeter.
Give the procedure for determination of calorific value of a liquid hydrocarbon accurately.
(C ) (i) Compare low temperature carbonization and high temperature carbonization.
(ii) Narrate the advantage of Otto Hofmann’s by product oven process for the manufacture of coke.
(D) A producer gas has the following composition by volume :
(i) Hz 19.4%                    (ii) CO 20.5%
(iii)N2 50.1 %                  (iv) CM, 4.0%
(v) C026.0%
Calculate the minimum volume of air needed for complete combustion of 100 m3 of the fuel gas. Also calculate the percentage of dry products of combustion if 30% excess air is used during combustion.
  UNIT-III
Q3 (i) The metal that can provide catholic protection to iron is :
(a) Aluminum                                     (b) Copper
(c) Nickel                                              (d) Tin
(ii) Choose the incorrect statement.
(a) Iron corrodes luster than. aluminum
(b) Impure metal corrodes corrosion increases with increase in temperature.
(c) The rate of metallic corrosion increases with increase in term premature.
(d)Formation of porous oxide film on metal surface prevents further corrosion of metal.
(B) Give the mechanism of electrochemical corrosion.
How material selection and proper design can prevent corrosion?
(D) Define fuel cell. Explain the construction and working of hydrogen oxygen fuel cell.
(b)   (i) Mineral oils are :
(a) Unstable                         (b) Costly
(c) Poor in oiliness             (d) Easily oxidized
(ii) Nylon 6-6is :
(a) a polyamide fiber                (b) a polyester fiber
(c) a polyethylene derivative   (d) None
(B )Describe the mechanism of thin film lubrication.
(C )What is Teflon ? Give its properties and uses.
(D) Giving the necessary chemical reactions, discuss the setting and hardening of Portland cement.
Q5 (A) (i) Give the chemical formula of acryl nitrite
(ii) Calculate the oxygen balance of NH4No3.
(B) (i) Describe a method in brief for industrial production of ethyl alcohol.
(ii) Give two properties and two industrial used of glycerol.
(C )What do you understand by explosive material? .Describe Its characteristics and uses.
(D) What are propellants? How are they classified? What are the requirements for the selection of
a parallel?
(a) Define corrosion.
(b) Give mechanism of wet corrosion (of oxygen absorption at cathode) by giving well labeled diagram and    concerned reactions (explaining) portion, should be very brief). How yellow rust is form?
(c ) Write short notes on any two of the following :
(i)Water line corrosion
(ii)Fuel cell
(iii)Sacrificial Anodic method of corrosion control
Unit-IV
Q4 (a) What is Portland Cement ?
(b)   (i) Give flow chart of manufacturing of Portland cement by west method.
(ii)Name the main three constituents of Portland cement  responsible for imparting strength, mentioning also order and days required.
(c)    (i)Give differences between thermosetting and thermoplastic polymers (at least giving four points)
(ii) Write a short notes on any one of the following :
(x) PVC
(y) ISI specification of cement
(d) (i) What are lubricants ? Give their advantages.
(ii) Write a short note any one of the following :
(x) Phenol formaldehyde polymer
(y)Mechanism of extreme pressure lubrication.
Unit –V
5.  (a) What are explosives ?
(b)(i) What is rocket propellant?
(Answer in 30-40 lines)
(ii)What is dynamite ? (Ans. In one line)
(iii)Write short notes on any two of the following :
(x) Ammonium soleplate
(y) Arcylonitrile
(z) Glycerol
(c ) (i) What is meant by oxygen balance of an explosive ?
(ii) Write short notes on any two of the following :
(x) Calcium phosphate
(y) Chloroform
(z) Ethyl Alcohol
(d) (i) Give four required qualities of an explosive (Ans. In 50-60 words)
(ii) Write short notes on any two of the following :
(x) Ammonium nitrate
(y) Benzene
(z) Caprolactum
 

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