UNIT 6.ppt PDF

PPT file only for reference This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only. Electroplating Process Depositio...

PPT file only for reference This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only. Electroplating Process Deposition of metal on substrate by electrochemical process. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Purpose and Applications of Electroplating 1.Improving appearance. 2.Increasing protection. 3.Special surface properties. 4.Engineering or mechanical properties. The applications of electroplating are as follows: 1.Steel parts on automobiles are often plated with chrome to help them resist corrosion. 2.Steel and aluminium components in light fixtures are coated with nickel and either chromium or brass to enhance their appearance. 3.Steel bolts are coated with zinc and cadmium to help them last longer, and copper and brass connectors are often plated with silver to prevent tarnishing and increase conductivity. Unit 6 Fuels Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Introduction A fuel is defined as any substance used to produce heat or power by combustion. Any chemical process accompanied by the evolution of light and heat is called combustion. It is also a exothermal oxidation process. It is simply the reaction of substances with oxygen and converts chemical Characteristics of a Good Fuel 1.It should ignite easily. The temperature of the fuel at which ignition starts and continues to burn without further addition of heat is called ignition temperature. It should be moderate for a good fuel. Very low ignition temperature leads to fire hazard and very high ignition temperature disfavours the starting of fire. 1.It should give out a lot of heat, that is, its specific heat should be high. 2.It should have low smoke and combustible matter such as ash. It should not give out harmful combustion products. This property depends on the nature of elements present in the fuel.  Characteristics of a Good Fuel 4. It should be inexpensive and readily available. 5. It should be easy to store and transport. 6. It should have low ash content. Ash reduces the calorific value of the fuel, causes hindrance to the flow of air and heat, reduces the specific heat and leads to unwanted disposable problems. Calorific Value The amount of heat obtained from the fuel is called its calorific value, it is expressed in : Units 1.Mean British Thermal Unit (BTU) 2.Calorie (cal) 1 BTU= 252 cal 1 cal/g= 1.8 BTU/lb Gross and Net Calorific Values 1.Higher calorific value (HCV) or gross calorific value 2.Lower calorific value (LCV) or net calorific value 1. Higher calorific value (HCV) or Gross calorific value Total amount of heat liberated when one unit of fuel is burnt completely Hydrogen is present in all fuels and when calorific value determined, hydrogen is converted into steam When product of combustion is cooled at room temperature, the latent heat of steam is also included in measurement of heat. The total heat calculated in this way is called HCV HCV> LCV or Gross> Net latent heat 2. Lower calorific value (LCV) or Net calorific value Water vapors escapes along with hot combustion gases, so it is not condensed. As a result less amount of heat available, the amount of available heat is called LCV  Determination of Calorific Value Theoretically Determination Q. Calculate the LCV of a fuel which has 8% H and HCV as 6500 cal/gm. Given latent heat of steam 587 cal/gm Bomb calorimeter Experimentally Determination Bomb calorimeter 1.For calorific values of solid and liquid fuels 2.Known amount of fuel is burnt at constant volume 3.Temperature of surrounding water increases as heat is produced. 4.Quantity of heat and calorific values are calculated. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights W = Weight of water, w = water equivalent of calorimeter. S = specific heat of water, T2 = final temp, T1 =initial temp, x = weight of fuel. On burning 0.83 gm of coal, the temperature of 3500 gm water increased from 25.5 0C to 29.2 0C. Water equivalent is 385 gm. Latent heat = 587 cal/gm Calculate the gross and net calorific value. [H % = 0.7%] Gross calorific value = (W+w)(T2-T1)/X Ans = 17318.68 cal/ gm = 17.31868 kcal/ g Solid Fuels – Coal Formed from dead plants buried for several million years. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Proximate Analyses of Coal It includes the determination of moisture content, volatile matter, ash and fixed carbon. In this analysis, the data varies with the procedure adopted for study. The content of moisture, volatile matter and ash are experimentally determined, while that of fixed carbon is calculated. Proximate Analysis 1.Moisture content: Lesser the moisture content, better is the quality of coal. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights 2. Volatile matter: Lesser the volatile matter, better is the rank of coal. 3. Ash content: Lower the ash content, better is the quality of coal. 4. Fixed carbon: Higher fixed carbon content, better is the quality of coal. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Semi-Solid Fuels – Some Recent Advances The term semi-solid fuel in modern context refers to non-volatile substances that are environmentally safe and produce no hazardous waste on burning. These have long shelf-life and their ignition can be easily started and stopped. To overcome these problems, developing countries are transforming coal into gaseous or liquid fuel formulations or converting it into low ash and low sulphur varieties. For example, a solvent-refined, semi-solid form of coal has been prepared by suspending pulverized coal in a solvent and treating it with hydrogen gas at high temperature and pressure. The product Engineering Chemistry (revised edition) compares well with high grade anthracite in ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Liquid fuels – Petroleum 1.Petroleum is made from the remains of plants and animals buried millions of years ago. 2.It is a non-renewable resource. 3.It contains straight or cycloparaffins. 4.Olefins 5.Aromatics 6.Other organic compounds containing N, O, S. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Composition Petroleum is a dark, greenish brown, viscous liquid that is found underground. It comprises hydrocarbons such as: 1.Straight paraffins or cycloparaffins such as methane, ethane, propane, butane, isobutane, pentane, hexane. 2.Olefins such as ethylene, butene, isobutene and acetylene, butadienes. 3.Aromatics such as benzene, naphthalene, cyclohexane, methyl cyclopentane. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 4.Some organic compounds containing Copyright©2014 Wiley India Pvt. Ltd. All Rights Production from Refining of Crude Oil The petroleum obtained by mining is viscous and dark coloured liquid. Due to the presence of sulphur, it has an unpleasant smell. It also contains impurities of sand, brine or sea water. Hence it is called crude oil. The important steps involved are: 1.Fractional distillation to give various fractions. 2.Conversion of less desirable fractions to valuable products by processes like cracking. 3.Treatment of fractions to remove undesirable substances. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Fractional Distillation Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Fractions of petroleum Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Cracking Cracking is decomposition of high molecular weight compounds (with high boiling points) to low molecular weigh compounds with low boiling points). Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights  475-5300C at 7-70 atm. Pdt separated by fractionating Simply by application of column heat and pressure. breaking of larger to smaller Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Fixed bed catalytic cracking Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Fluidized-bed catalytic cracking: used to perform cracking continuously. The catalyst is suspended in a stream of oil vapors. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights The spent catalyst flows out of the bottom of furnace and regenerated, while fresh are added from top. Temp is 450- 550C and pressure is 1-2 atm. Cracking takes place on surface of turbulent catalyst as it circulates with oil vapor. The cracked pdt. (low boiling) rise up to the top of reactor and enter the fractionating column. The cracked gases and gasoline are removed from top of fractionating column, from there they sent to cooler for condensing gasoline. It contains higher portion of aromatic and isoparaffin than thermal cracking. For regeneration, the catalyst remove continuously from reactor and burnt off at 590Cto free it from tarry carbon residue. The fluidized (moving) bed cracking has the following advantages over fixed-bed cracking: 1.Better contact with the feed and the catalyst, enabling uniform temperature and efficient heat transfer. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 2.The catalyst can be regenerated and used Copyright©2014 Wileyagain for India Pvt. Ltd. the All Rights Catalytic Reforming Reforming is a process of converting low octane naphthas into high octane gasoline. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights  Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Knocking Knocking in Spark Ignition Engines and Octane Number Petrol is used in spark ignition engines. The rapid compression of the fuel-air mixture heats the engine, and it detonates without the spark being passed. This causes a violent jerk to the piston giving a metallic sound called knocking. Octane number is the percentage volume of isooctane in the isooctane-heptane mixture that matches the knocking characteristics of the fuel being tested is called the octane number. Molecular structure affects the octane number. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Knocking in Compression Ignition Engines and Cetane Number Diesel is used in compression ignition engines. Cetane number represents the spontaneous ignition temperature of a particular diesel fuel. It is the percentage of cetane present in a mixture of cetane and alpha- methylnaphthalene which matches the fuel under test in ignition property. Engineering Chemistry (revised edition) ISBN: 978-81-265-4475-2 Copyright©2014 Wiley India Pvt. Ltd. All Rights Battery Overview Steve Garland Kyle Jamieson  Outline Why is this important? Brief history of batteries Basic chemistry Battery types and characteristics Case study: ThinkPad battery technology  Motivation To exploit properties of batteries in low-power designs – Protocols (Span , MAC layer) – Hardware (Cricket) – Example: n cells; discharge from each cell, round-robin fashion [Chiasserini and Rao, INFOCOM 2000]  Battery (Ancient) History 1800 Voltaic pile: silver zinc 1836 Daniell cell: copper zinc 1859 Planté: rechargeable lead-acid cell 1868 Leclanché: carbon zinc wet cell 1888 Gassner: carbon zinc dry cell 1898 Commercial flashlight, D cell 1899 Junger: nickel cadmium cell  Battery History 1946 Neumann: sealed NiCd 1960s Alkaline, rechargeable NiCd 1970s Lithium, sealed lead acid 1990 Nickel metal hydride (NiMH) 1991 Lithium ion 1992 Rechargeable alkaline 1999 Lithium ion polymer  Battery Nomenclature Duracell batteries 9v battery 6v dry cell Two cells A real battery Another battery More precisely  The Electrochemical Cell e consumer salt bridge oxidation reduction at zinc at copper anode ZnSO4 CuSO 4 cathode Half Cell I Half Cell II The Electrochemical Cell (2) Zinc is (much) more easily oxidized than Copper Zn  Zn 2  2e  ( I.) Cu 2  2e   Cu ( II.) Maintain equilibrium electron densities Add copper ions in solution to Half Cell II Salt bridge only carries negative ions – This is the limiting factor for current flow – Pick a low-resistance bridge The Electrochemical Series Most wants to reduce (gain But, there’s a reason it’s a sodium drop electrons) Gold Iron Mercury Zinc Silver Aluminum Copper Magnesium Lead Sodium Potassium Nickel Lithium Cadmium Most wants to oxidize (lose electrons)  Battery Characteristics Size – Physical: button, AAA, AA, C, D,... – Energy density (watts per kg or cm3) Longevity – Capacity (Ah, for drain of C/10 at 20°C) – Number of recharge cycles Discharge characteristics (voltage drop)  Further Characteristics Cost Behavioral factors – Temperature range (storage, operation) – Self discharge – Memory effect Environmental factors – Leakage, gassing, toxicity – Shock resistance  Primary (Disposable) Batteries Zinc carbon (flashlights, toys) Heavy duty zinc chloride (radios, recorders) Alkaline (all of the above) Lithium (photoflash) Silver, mercury oxide (hearing aid, watches) Zinc air  Standard Zinc Carbon Batteries Chemistry Zinc (-), manganese dioxide (+) Zinc, ammonium chloride aqueous electrolyte Features +Inexpensive, widely available – Inefficient at high current drain – Poor discharge curve (sloping) – Poor performance at low temperatures  Heavy Duty Zinc Chloride Chemistry Batteries Zinc (-), manganese dioxide (+) Zinc chloride aqueous electrolyte Features (compared to zinc carbon) +Better resistance to leakage +Better at high current drain +Better performance at low temperature  Standard Alkaline Batteries Chemistry Zinc (-), manganese dioxide (+) Potassium hydroxide aqueous electrolyte Features +50-100% more energy than carbon zinc +Low self-discharge (10 year shelf life) ±Good for low current (< 400mA), long-life use – Poor discharge curve Alkaline-Manganese Batteries (2) Alkaline Battery Discharge Lithium Manganese Dioxide Chemistry Lithium (-), manganese dioxide (+) Alkali metal salt in organic solvent electrolyte Features +High energy density +Long shelf life (20 years at 70°C) +Capable of high rate discharge – Expensive Lithium v Alkaline Discharge  Secondary (Rechargeable) Batteries Nickel cadmium Nickel metal hydride Alkaline Lithium ion Lithium ion polymer Lead acid  Nickel Cadmium Batteries Chemistry Cadmium (-), nickel hydroxide (+) Potassium hydroxide aqueous electrolyte 1.4 V Features + Rugged, long life, economical + Good high discharge rate (for power tools) – Relatively low energy density – Toxic Applications: pocket calculator, electronic flash light, Emergency light, portable electronic & toys  NiCd Recharging Over 1000 cycles (if properly maintained) Fast, simple charge (even after long storage) C/3 to 4C with temperature monitoring Self discharge 10% in first day, then 10%/mo Trickle charge (C/16) will maintain charge Memory effect Overcome by 60% discharges to 1.1V NiCd Memory Effect  Nickel Metal Hydride Batteries Chemistry LaNi5, TiMn2, ZrMn2 (-), nickel hydroxide (+) Potassium hydroxide aqueous electrolyte Features +Higher energy density (40%) than NiCd +Nontoxic – Reduced life, discharge rate (0.2-0.5C) – More expensive (20%) than NiCd  Li- ion Electrolyte cathode Graphite anode Li-Ion battery Principle D Q1: Based on the extent of dissociation, electrolytes are classified into _____ types. a) One b) Two c) Three d) Four D Q2: Hydrochloric acid is an example of ______ electrolyte. a) Strong b) Weak c) Not sure d) Super weak D Q3: Acetic acid is an example of ______ electrolyte. a) Strong b) Weak c) Not sure d) Super weak D Q4: Conductivity is defined as the ability to carry a) Voltage b) Resistance c) Current d) All of the mentioned D Q5. The reciprocal of conductivity is a) Viscosity b) Resistivity c) Turbidity d) None of the mentioned D Q6. The internationally recommended unit for conductance is a) Poise b) Dyne c) Ohm d) Siemens D Q7. The cell constant is defined as the ratio of a) Area of either electrodes to the length between the electrodes b) Length between the electrodes to the area of either electrodes c) Length between the electrodes to the volume of either electrode d) Resistivity to conductivity Q8. Dilution means an increase in the amount of a) Solute b) Solvent c) Electrolyte d) All of the mentioned Q9: An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to a) increase in both i.e. number of ions and ionic mobility of ions. b) increase in number of ions c) increase in ionic mobility of ions d) 100% ionization of electrolyte at normal dilution Q10: The highest electrical conductivity of the following aqueous solutions is of a) 0.1 M acetic acid b) 0.1 M chloroacetic acid c) 0.1 M fluoroacetic acid d) 0.1 M difluoroacetic acid Q11: Which of the following is a strong electrolyte in aqueous solution? a) HNO2 b) HCN c) HCl d) NH3 Q12 By losing one or two electrons atoms of metal are a. oxidized b. reduced c. hydrogenated d. sublimated 13. The electrochemical series shows equations representing reactions of which type? a. Oxidation b. Reduction c. Neutralisation d. Precipitation Q14 In a cell, what type of charged particle flows in the wires? a. Atoms b. Molecules c. Ions d. Electrons Q15 Salt bridge transfers 16. Temperature for the measurement of standard electrode potential is a. electrons A.298K b. anion B.300K c. current C.30K d. ions D.310K Q1: Based on the extent of dissociation, electrolytes are classified into _____ electrolytes. a) Strong and weak b) Weak, strong and super strong c) Strong, weak and medium d) Super strong and strong Q2: CH3COOH is an example of ______ electrolyte. a) Strong b) Weak c) Not sure d) Super strong Q3: NaCl is an example of ______ electrolyte. a) Strong b) Weak c) Not sure d) Super weak Q4: An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to a) increase in both i.e. number of ions and ionic mobility of ions. b) increase in number of ions c) increase in ionic mobility of ions d) 100% ionization of electrolyte at normal dilution Q5: Conventionally, electrode potential refers to a) Oxidation b) Reduction c) Neutralization d) charge potential Q6: Which of the following is a strong electrolyte in aqueous solution? a) HNO2 b) HCN c) NaCl d) NH3 Q7: The highest electrical conductivity of the following aqueous solutions is of a) 0.2 M acetic acid b) 0.2 M chloroacetic acid c) 0.2 M fluoroacetic acid d) 0.2 M difluoroacetic acid Q8: In Redox reactions, electrons may be a) gained b) lost c) shared d) gained and lost Q9 Which of the following does not conduct electricity? (a) Fused NaCl (b) Solid NaCl (c) NaCl aquous solution (d) Copper Q10. Which of the following electrolytic solutions has the least specific conductance? a. 0.02 N b. 0.2 N c. 2 N d. 0.002 N Q11 Pure water does not conduct electricity because it is a. basic b. almost not ionised c. decomposed easily d. acidic Q12. During electrochemical process (a) Gibbs free energy increases. (b) Gibbs free energy remains constant. (c) no prediction can be about Gibbs free energy. (d) Gibbs free energy decreases. 13. A metal having negative reduction potential when dipped in the solution of its own ions, has a tendency : (a) to pass into the solution (b) to be deposited from the solution (c) to become electrically positive (d) to remain neutral Q14: The standard reduction electrode potential values of the element A, B and C are + 0.68, –2.50, and –0.50 V respectively. The order of their reducing power is : (a) A > B > C (b) A > C > B (c) C > B > A (d) B > C > A Q15 Stronger the oxidizing agent greater is the a. Oxidation potential b. Reduction potential c. Redox potential d. emf of cell 16. Molten NaCl conducts electricity due to the presence of a. Free electrons b. Free molecules c. Free ions d. Atoms of Na and Cl 17 Electricity in voltaic cell is produced due to a. neutralization b. oxidation c. reduction d. both b & c D Q1. Chemical Composition of rust a) Fe2O3. xH2O (s) b) Fe2O3. xH2O (l) c) Fe2O3. xH2O (g) d) Fe2O3. xHCl D Q2: Corrosion between the dissimilar metals is called as__________ a) Galvanic corrosion b) Dry corrosion c) Oxidation corrosion d) Concentration cell corrosion D Q3. Corrosion due to the formation of cavities around the metal is called as the___________ a) Pitting corrosion b) Soil corrosion c) Water line corrosion d) Galvanic corrosion S Q4. Corrosion due to difference in water level is__________ a) Soil corrosion b) Oxidation corrosion c) Pitting corrosion d) Water line corrosion D Q5. The process of deterioration of a metal due to unwanted chemical or electrochemical interaction of the metal with its environment is called ___ a) Electrolysis b) Electrodialysis c) Corrosion d) Deposition S Q6. Which of the following is the most stable state of metal? a) Ore of metal b) Pure metal c) Corroded metal d) Metal ion D Q7: Due to corrosion, useful properties of metals such as malleability, ductility and electrical conductivity are lost. a) True b) False c) partially true d) partially false D Q8: What is meant by corrosion? a) Chemical reaction between anode, cathode and electrolyte, which leads to loss of metal b) Deterioration of metals due to reaction with its environment c) Both a. and b. d) None of the above D Q9: Which type of chemical reaction is observed at cathode, in electrochemical corrosion? a) Oxidation reaction b) Peretectic reaction c) Reduction reaction d) None of the above S Q10: Electrochemical corrosion takes place on a) Anodic area b) Cathodic area c) Near cathode d) Near anode D Q11. Standard electrode potential of hydrogen is, a) 1.00 V b) 0.00 V c) 0.01 V d) 0.001 V S Q12. In differential aeration corrosion, poor oxygenated parts are, a) Anodic b) Cathodic c) Corroded d) None of above D Q13. Pitting corrosion is a __________ accelerated attack. a) Non- localized b) Localized c) Diverse d) None of above D 14. Lower is pH , corrosion is, a. Greater b. Lower c. Constant d. None of above D 15. Smaller the grain size, corrosion is, a. Greater b. Lower c. Constant d. Doesn’t affected D 16. Process of corrosion enhanced by, a. AIR & Moisture b. Electrolytes in water c. Metallic impurities d. All of above. D 17. Evolution of hydrogen type corrosion occurs in _______ environment. a. Acidic b. Neutral c. Basic d. Alkaline D 18. Conversion of Cu to Cu2+ is, a. Oxidation b. Reduction c. Redox reaction d. None of above D 19. Conversion of Fe2+ to Fe is, a. Oxidation b. Reduction c. Redox reaction d. None of above D Q20: Liquid metal mercury dissolves most metals by forming amalgams. It is an example of a. Oxidation corrosion b. Liquid corrosion c. Options (a) and (b) are correct d. Galvanic Corrosion D Q21: Corrosion of an underground pipe is an example of a. Soil corrosion b. Soil erosion c. Soil destruction d. Soil consumption D Q22: Temperature affects the rate of corrosion: a. True b. False c. Depends on metal d. Depends on condition D Q23: pH of a medium has an effect on rate of corrosion a. True b. False c. Depends on metal d. No affect at all D Q1: Electroplating is done a) To protect the metals against corrosion b) To give shiny appearance to articles c) To repair the worn out materials d) All of these D Q2. Which of the following is a property of ceramics? a) Low strength b) Low melting point c) Resistant to corrosion d) Bad insulation D Q3. Corrosion due to the corrosiveness of the soil is called as___________ a) Soil corrosion b) Oxidation corrosion c) Galvanic corrosion d) Concentration cell corrosion D Q4: Acidic media are more corrosive than neutral media. a) True b) False c) Not always true d) Not always false D Q5: Destruction of metal starts ________. a) At the surface b) Just on layer below from surface c) In the middle d) At the bottom D Q6: Corrosion is a process reverse of ______ of metal. a) Destruction b) Extraction c) Rusting d) Galvanizing D Q7: Conversion of Zn to Zn2+ is, a) Oxidation b) Reduction c) Redox reaction d) None of above D Q8. Corrosion process is nothing but ________ a) Reduction b) Oxidation c) Protection d) None of above D Q9. Galvanization is a process of coating ___ on iron a) Zn b) Fe c) Na d) K D Q10. Iron undergoes severe corrosion in ______ a) Hard water b) Software c) Demineralize water d) Distilled water Q11 Corrosion is the _________ of metal properties a. deterioration b. improvement c. enhancement d. All the above Q12: Corrosion is a. thermodynamically favorable process b. thermodynamically unfavorable process c. not related to thermodynamics d. mechanical process Q13 Nature of the metal has an effect on corrosion a. True b. False c. Only true of Fe metal d. Only true of Cu metal Q14. Metallic coating a. save metals from corrosion b. degrades metal properties c. enhance corrosion d. accelerate corrosion  D 1. In presence of which gas is the fuel burnt to generate energy in form of heat? a) Oxygen b) Hydrogen c) Methane d) Nitrogen D2. Which are the main constituents of fuel from given options? a) Carbon and Nitrogen b) Oxygen and Hydrogen c) Carbon and Hydrogen d) Helium and Oxygen D3. Ignition temperature is a. Lowest temperature at catch fire b. Higher temperature at catch fire c. Any temperature d. None of these D4. The products of combustion are a. Carbon dioxide and water b. Oxygen and water c. Only carbon dioxide d. Only oxygen D 5: The major constituent of natural gas is a. Methane b. Ethane c. Propane d. Butane D 6: The antiknock property of the fuel depends on its a. Self-ignition temperature b. Molecular structure c. Chemical composition d. All of the above  D 7: The following is used for rating for Compression ignition engines. a. Octane number b. Cetane number c. Butane number d. All of the above D 8: Which fuels are used for running automobiles? a. Wood b. Coal c. Diesel d. Charcoal D 9. Benefits of using small cells could be A. lightweight B. high voltage C. constant voltage D. all of them D 10. Combustion is a reaction in which a Substance reacts with- a. Hydrogen b. Nitrogen c. Oxygen d. Chlorine D 11. Fuel may be- a. Solid b. Liquid c. Gas d. All of these D 12. Combustion is a- a. Physical process b. Chemical process c. Both (a) & (b) d. None of these D 13. The lowest temperature at which a Substance catches fire is called its- a. Boiling point b. Melting point c. Ignition temperature d. Critical temperature D 14. Which one of the following is non Combustible? a. Stone piece b. Paper c. Straw d. Matchsticks D15: Which of the following is inflammable Substances? a. Petrol b. Wood c. Paper d. Straw D 16. Essential requirements for producing fire are: a. Fuel b. Air c. Heat d. All of these D 17: Fire extinguisher- a. Cut off the supply of air b. Bring down the temperature of fuel c. Both (a) & (b) d. None of these D 18. For combustion ________is necessary a. Air b. Water c. Paper d. KOH D 19. Rapid combustion is a. When gas burns, it produces heat and light b. When material suddenly burst into flames c. When there is evolution of heat d. None of these D 20. Good fuel is a. Readily available b. Cheap c. Burn easily in air d. All of these D 21. Ideal fuel has ____ calorific value a. Low b. High c. Moderate d. Zero D 22. Calorific value gives the a) Fuel efficiency b) Amount of heat c) Amount of light d) None of these D 23. Incomplete combustion gives a. CO2 b. CO c. Carbon d. None of these D 24. Which of the following is/are carbon fuel a. Wood b. Coal c. Petroleum d. All of these D 25. Combustion of most fuels releases a. CO2 b. SO2 c. NO2 d. Oxygen D 26. Best extinguisher for inflammable Materials is a. Water b. SO2 c. CO2 d. CO D 27: A fuel cell is used to convert chemical energy into a) Mechanical energy b) Solar energy c) Electrical energy d) Potential energy D 28. The residual product discharged by the hydrogen-oxygen cell is a) Hydrogen peroxide b) Alcohol c) Water d) Potassium permanganate D 29. Octane number is a rating of _______ a) petrol knocking b) diesel knocking c) petrol cracking d) diesel cracking D 30: 2. Which of the following element has 100% anti knocking? a) 2-methyl naphthalene b) heptadecane c) CH3-(-CH2-)14-CH3 d) 3-methyl naphthalene D 31.An electrochemical cell in which a fuel gives up electrons at one electrode and oxygen gain electrons at other electrode, is known as a) fuel cell b) electrolytic cell c) oxygen cell d) electron cell 32D. By passing electricity through electrochemical cells, they can be a) recharged b) charged c) discharged d) deployed D 33. Advantage of fuel cell over petrol is its only product a) oxygen b) water c) nitrogen d) CO2 D 34. Primary battery is such a battery a. which can be recharged. b. which cannot be reconditioned by replacing chemical. c. which cannot be reused. d. which cannot be recharged. D 35. The secondary battery is such a battery a. which cannot be recharged. b. which can be recharged. c. which can be reused after replacing its chemical. d. which is charged by primary cells. 36. Internal resistance of a battery cell increases with a. increases in concentration of electrolyte. b. increase in distance between two electrodes. c. increases in area of the plates inside the electrolyte. d. increase in size of the electrodes.