In a SI engine, which one of the following is the correct order of the fuels with increasing detonation tendency? (a) Paraffins, olefins, naphthenes, aromatics (b) Aromatics, naphthenes, paraffins, olefins (c) Naphthenes, olefins, aromatics, paraffins (d) Aromatics, naphthenes, olefins, paraffins

1 Answer

Answer :

Ans :d

Related questions

Description : Which of the following has the highest octane number? (A) Aromatics (B) i-paraffins (C) Naphthenes (D) Olefins

Last Answer : (A) Aromatics

Description : H/C ratio (by weight) for the same number of carbon atoms is the highest in case of (A) Aromatics (B) Paraffins (C) Olefins (D) Naphthenes

Last Answer : (D) Naphthenes

Description : Which of the following is the easiest to crack? (A) Paraffins (B) Olefins (C) Naphthenes (D) Aromatics

Last Answer : (A) Paraffins

Description : Reforming converts (A) Olefins into paraffins (B) Naphthenes into aromatics (C) Naphthenes into olefins (D) Naphthenes into paraffin

Last Answer : (B) Naphthenes into aromatics

Description : For C.I. engines fuel most preferred are a) aromatics b) paraffins c) olefins d) napthenes

Last Answer : Answer: b Explanation: For C.I. engines fuel most preferred are paraffins and for S.I. engines fuel most preferred are aromatics.

Description : For S.I. engines fuel most preferred are a) aromatics b) paraffins c) olefins d) napthenes

Last Answer : Answer: a Explanation: For S.I. engines fuel most preferred are aromatics while for C.I. engines fuel most preferred are paraffins.

Description : Pick out the wrong statement about the smoking tendency of various hydrocarbon constituents of kerosene. (A) Smoking tendency of hydrocarbons increases in the order: paraffins → isoparaffins → naphthenes → aromatics (B) Smoking tendency of paraffins increases with decrease in its molecular weight

Last Answer : (B) Smoking tendency of paraffins increases with decrease in its molecular weight

Description : Which of the following has the highest gum forming tendency in gosoline? (A) Paraffins (B) Diolefins (C) Aromatics (D) Naphthenes

Last Answer : (B) Diolefins

Description : Which of the following hydrocarbons of same carbon atoms has minimum smoking tendency? (A) Paraffins (B) Naphthenes (C) Aromatics (D) Iso-paraffins

Last Answer : (A) Paraffins

Description : Choose the correct statement. (A) Octane number of i-octane is zero (B) Octane number of paraffins increases with increasing number of carbon atoms (C) Branched chain paraffins have higher octane ... atoms (D) The aromatics have lower octane number than naphthenes with same number of carbon atoms

Last Answer : (A) Octane number of i-octane is zero

Description : Isomerisation converts the __________ tot-paraffins. (A) Paraffins (B) Olefins (C) Naphthenes (D) None of these

Last Answer : (A) Paraffins

Description : The main reaction in reforming is the (A) Dehydrogenation of naphthenes (B) Hydrogenation of naphthenes (C) Hydrocracking of paraffins (D) Saturation of olefins

Last Answer : (A) Dehydrogenation of naphthenes

Description : Pick out the wrong statement. (A) Lower boiling paraffins have higher octane number than higher paraffins (B) Dehydrogenation of naphthenes to aromatics is a desirable reaction in reforming ... is dearomatised kerosene (D) Catalyst used in catalytic reforming is platinum on silica-alumina base

Last Answer : (C) The most ideal feedstock for thermal reforming is dearomatised kerosene

Description : Which is the most desirable component of a good quality kerosene? (A) i-paraffins (B) Aromatics (C) n-paraffins (D) Naphthenes

Last Answer : (C) n-paraffins

Description : Which is the most undesirable component in kerosene? (A) Aromatics (B) i-paraffins (C) n-paraffins (D) Naphthenes

Last Answer : (A) Aromatics

Description : Extractor temperature is maintained at -20°C in Edeleanu process to reduce the __________ of kerosene. (A) Smoke point (B) Paraffins (C) Aromatics (D) Naphthenes

Last Answer : (B) Paraffins

Description : Smoke point of a test sample of kerosene is found to be 15 mm. On removal of __________ from it, the smoke point rises to 25 mm. (A) n-paraffins (B) Olefins (C) Aromatics (D) None of these

Last Answer : (C) Aromatics

Description : Pyrolysis of kerosene or natural gasoline is done to produce mainly the (A) Olefins and aromatics (B) Lighter paraffins (C) Stabilised gasoline (D) Diesel

Last Answer : (A) Olefins and aromatic

Description : Which of the following has the lowest cetane number? (A) Aromatics (B) i-paraffins (C) Naphthene (D) Olefins

Last Answer : (A) Aromatics

Description : Which of the following fuel has little tendency towards detonation? a) Benzene b) Iso-octane c) Normal heptane d) Alcohol

Last Answer : Answer: b Explanation: Benzene has little tendency towards detonation.

Description : Reference fuels for knock rating of SI engine fuels would include (a) Iso octane alpha methyl naphthalene (b) Normal octance and aniline (c) Isooctance and n octane (d) N heptane and iso octane

Last Answer : Ans : d

Description : The tendency of a petrol engine to knock increases by a. supercharging b. scavenging c. increasing the engine horse power d. reducing the spark advance

Last Answer : ANSWER a. supercharging

Description : HUCR is the highest compression ratio at which the A. engine can be run B. engine gives maximum output C. engine is most efficient D. fuel can be used in a test engine without detonation

Last Answer : ANSWER : D

Description : As a result of detonation in an I.C engine, following parameter attains a high value A. peak temperature B. peak pressure C. rate of pressure rise D. rate of temperature rise

Last Answer : ANSWER : C

Description : The compression ratio cannot be increased beyond certain limit as it results in a. auto-ignition of fuel b. detonation c. engine knocking d. all the above

Last Answer : ANSWER d. all the above

Description : Which of the following factors increases the tendency of knocking in the CI engines? (a) Increasing both the r and coolant temperatures (b) Increasing both the speed and the injection advance (c) Increasing the speed, injection advance and coolant temperature (d) Increasing the compression ratio

Last Answer : Ans :c

Description : In SI engines knocking can be reduced by (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature

Last Answer : Ans :c

Description : Disadvantage of hydrogen as a fuel in IC engine is a) storage is safe b) low NOx c) detonating tendency d) easy handling

Last Answer : Answer: c Explanation: None.

Description : The tendency of knocking in CI engine reduces by (a) High self ignition temperature of fuel (b) Decrease in jacket water temperature (c) Injection of fuel just before TDC (d) Decrease in injection pressure

Last Answer : Ans :c

Description : The tendency of a diesel engine to knock increases if a. engine speed is increased b. engine power is increased c. cetane number of the fuel is increased d. compression ratio is increased

Last Answer : ANSWER d. compression ratio is increased

Description : As a result of detonation in Internal combustion engines the following parameter attains very high value. a. peak pressure b. rate of rise of pressure c. rate of rise of temperature. d. peak temperature.

Last Answer : ANSWER b. rate of rise of pressure

Description : Detonation can be controlled by a. varying the compression ratio b. using lean mixture c. retarding the spark timing d. reducing the rpm

Last Answer : ANSWER c. retarding the spark timing

Description : Which is almost absent in crude petroleum? (A) Olefins (B) Mercaptans (C) Naphthenes (D) Cycloparaffins

Last Answer : (B) Mercaptans

Description : Liquefied Petroleum Gas (LPG) is mainly a mixture of (A) Propane & butane (B) Methane & ethane (C) High boiling olefins (D) High boiling naphthenes

Last Answer : (A) Propane & butane

Description : The general formula of naphthenes is (A) CnH2n + 2 (B) CnH2n-6 (where, n ≥ 6) (C) CnHn-4 (D) Same as that for olefins i.e. CnH2n

Last Answer : (B) CnH2n-6 (where, n ≥ 6)

Description : CnH2n is the general formula for (A) Olefins (B) Naphthenes (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

Description : Enlist the measures of control detonation in SI engine. 

Last Answer : Detonation can be control by any or all of the following techniques: 1) Use of a fuel with high octane rating. 2) Enriching the air-fuel ratio. 3) Reducing peak cylinder pressure. 4) decreasing ... . 8) Retarding spark. 9) Water injection 10) Use of high octane fuel can eliminate detonation.

Description : Pick out the correct statement. (A) Paraffins have higher octane number than corresponding iso-paraffin (B) Paraffins have lower smoke point than aromatics

Last Answer : (B) Paraffins have lower smoke point than aromatics

Description : Ignition timing of a multi-cylinder SI engine can be adjusted by A. rotating the cam shaft B. adjusting the generator pulley C. rotating the distributor D. adjusting the pump pulley

Last Answer : ANSWER : C

Description : Morse test is conducted on the engine to calculate the mechanical efficiency of A. single cylinder CI engine B. single cylinder SI engine C. only on two stroke engines D. multi cylinder engine

Last Answer : ANSWER : D

Description : The compression ratio in a Spark Ignition (SI) engine is generally in between a. 7 to 10 b. 10 to 14 c. 14 to 18 d. 18 to 22 (Ans:a)

Last Answer : Which of the following is not true for two stroke engine as compared to four stroke engine? a. Less cooling is required b. Greater lubrication is required c. More uniform torque on crankshaft d. Complete exhaust of products of combustion (Ans:a)

Description : In a morse test for a 2 cylinder, 2 S SI engine, the brake power was 9 kW. Whereas the brake power of individual cylinders with spark cut off were 4.25 kW and 3.75 kW. The mecheffic of the engine is (a) 90% (b) 80% (c) 45.5% (d) 52.5%

Last Answer : Ans :a

Description : In a variable speed SI engine, the maximum torque occurs at the maximum (a) Speed (b) Brake power (c) Indicated power (d) Volumetric efficiency

Last Answer : Ans :d

Description : Velocity of flame propagation in SI engine is maximum for a fuel air mixture which is (a) 10% richer than stoichiometric (b) Equal to stoichiometric (c) More than 10% richer than stoichiometric (d) 10% leaner than stoichiometric

Last Answer : Ans :a

Description : A two stroke engine has a speed of 750 rpm. A four stroke engine having an identical cylinder size runs at 1500 rpm. The theoretical output of the two stroke engine will (a) Be twice that of the four stroke ... ) Be the same as that of the four stoke (d) Depend upon whether it is a CI or SI engine

Last Answer : Ans :c

Description : The method of determination of indicated power of multi cylinder SI engine is by use of (a) Morse test (b) Prony brake test (c) Motoring test (d) Heat balance test

Last Answer : Ans : a

Description : For the same capacity engines, the compression ratio of diesel engine a. is lower than the compression ratio of SI engine b. is higher than the compression ratio of SI engine c. is same as the compression ratio of SI engine d. cannot say

Last Answer : ANSWER b. is higher than the compression ratio of SI engine

Description : How the efficiency of the SI engine is affected by the specific heat ratio (γ) of the working fluid? a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working ... not affected by change in specific heat ratio (γ) of the working fluid d. none of the above

Last Answer : ANSWER a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working fluid

Description : Olefins are generally represented by a) CnHn b) CnH2n c) CnH2n+2 d) CnH2n-6

Last Answer : Answer: a Explanation: Olefins are represented by CnHn and paraffins are generally represented by CnH2n+2.

Description : Paraffins have molecular structure of a) chain saturated b) chain unsaturated c) ring saturated d) ring unsaturated

Last Answer : Answer: a Explanation: None.