Chemistry · General Awareness

Carbon and Fossil Fuels

1,898 Questions

Review fundamental concepts regarding carbon compounds, coal distillation, and fossil fuel formation. This segment covers the chemical properties and industrial applications of natural gas and crude oil. Practicing these questions will strengthen your chemistry foundation for general science sections.

Coal distillationPetroleum formationProperties of crude oilNatural gas applications

Carbon and Fossil Fuels Questions

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

Complete combustion of alkene require sufficient :

  1. oxygen

  2. hydrogen

  3. nitrogen

  4. sulphur
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Complete combustion of alkene require sufficient oxygen.
Alkene on combustion in presence of sufficient oxygen will give carbon dioxide and water.
$\displaystyle CH _2=CH _2 + 3O _2 \rightarrow 2CO _2 + 2H _2O$

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

Alkanes are used as fuel :

  1. because there is evolution of large amount of heat during combustion

  2. because there is evolution of large amount of heat during conduction

  3. because there is evolution of large amount of heat during neutralization

  4. because there is absorption of large amount of heat during combustion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alkanes are used as fuel, because there is evolution of large amount of heat during combustion. Here, the purpose is to obtain as much heat as possible from given mass of fuel.

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

LPG burns more cleanly than higher molecular weight hydrocarbon :

  1. because it releases volatile pollutants

  2. because it releases less pollutants

  3. because it releases pollutants which are toxic

  4. because it releases more pollutants
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

LPG burns more cleanly than higher molecular weight hydrocarbon because it releases less pollutants.  Being a gas, LPG does not cause ground or water pollution hazards, but it  causes air pollution.
Note: LPG is liquefied petroleum gas which is compound of butane and propane used in cooking fuel ( in heating appliances, cooking equipment) , motor fuel (in vehicles) and refrigeration.

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

Benzene when heated in air burns with ________ and produces $CO _2$ and $H _2O$.

  1. sooty flame

  2. non-sooty flame

  3. light color flame

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Benzene when heated in air burns with sooty flame and produces $\displaystyle CO _2 $ and $\displaystyle H _2O$.
$\displaystyle C _6H _6 + \dfrac {15}{2} O _2 \rightarrow 6CO _2 + 3H _2O$
Note: Incomplete combustion of unsaturated hydrocarbons give sooty flame due to presence of black unburnt carbon particles.

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

LPG releases  ______ of the $CO _2$ per KWh produced by oil.

  1. 89%

  2. 81%

  3. 79%

  4. 0%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

LPG releases 81% of the $CO _2$ per Kwh produced by oil.
LPG, at atmospheric pressure, has a higher calorific value 94 MJ/m$^3$ which equivalent to 26.1 kWh/m$^3$.

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

Carbon monoxide is produced by :

  1. incomplete combustion of fuels

  2. complete combustion of fuels

  3. neutralization of fuels

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carbon monoxide is produced by incomplete combustion of fuels.
The complete combustion of fuels will give carbon dioxide.
$\displaystyle C + \dfrac {1}{2}O _2 \rightarrow CO$
$\displaystyle C +  O _2 \rightarrow CO _2$

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

LPG is liquefied petroleum gas which is a compound of butane and propane and used as :

  1. cooking fuel

  2. motor fuel

  3. refrigeration

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

LPG is liquefied petroleum gas which is a compound of butane and propane. It is used as cooking fuel (in heating appliances, cooking equipment), motor fuel (in vehicles) and refrigeration.


Hence the correct option is D.

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

LPG has a lower energy density than either petrol or fuel-oil, so the equivalent  ______ is higher.

  1. fuel-consumption

  2. fuel-absorption

  3. fuel density

  4. fuel capacity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

LPG has a lower energy density than either petrol or fuel-oil, so the equivalent fuel-consumption is higher.
Lower energy density means lesser amount of energy is released during combustion of unit mass of fuel. Hence, to obtain certain quantity of fuel more fuel should be combusted.

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

LPG can be used as a power source for :

  1. combined heat and power technologies (CHP)

  2. combined heat and energy technologies ( CHP)

  3. combined heat and coal technologies (CHP)

  4. heat and power technologies
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

LPG can be used as a power source for combined heat and power technologies (CHP).
Combined  heat and power (CHP) is the simultaneous generation of electricity and useful heating from the combustion of a fuel. It is a thermodynamically efficient use of fuel.

Multiple choice chemistry hydrocarbons introduction to alkenes - ethyne acetylene alkynes

A mixture of oxygen and ethyne is burnt for welding. Why a mixture of ethyne and air is not used?

  1. ethene can not burn in air

  2. incomplete combustion takes place

  3. ethene burn in air with explosion

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When ethyne is burnt in air incomplete burning takes place and produce sooty flame due to limited supply oxygen present in the air.


 However, if ethyne is burnt in oxygen, it gives a clean flame with high temperature (3000°C ) due to complete combustion of ethyne.

 Hence, This oxy-acetylene flame is used for welding and it is not possible to attain such a high temperature with air. Due this reason a mixture of ethyne and air is not used for welding.

Multiple choice methods of purification of organic compounds methods of purification - organic compounds organic chemistry - some basic principles and techniques organic chemistry : some basic principles and techniques chemistry biochemical techniques

Refining of petroleum does not involve.

  1. Simple distillation

  2. Steam distillation

  3. Fractional distillation

  4. Distillation under reduced pressure
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

The steam distillation process works on the principle that when a mixture of two or more undissolved liquids are heated, while ensuring that the surfaces of both liquids are in contact with the atmosphere, the vapor pressure exerted by the system increases. This method is used for the refining of petroleum. 


So, simple distillation, fractional distillation, distillation under reduced pressure are not involved in the refining of petroleum.

Options A, C, and D are correct answers.

Multiple choice chemistry air and water pollution ways to prevent air pollution ways to reduce air pollution reducing air pollution

Carbon monoxide is naturally produced by oxidation of   X  , a gas present in swamp area while it can be produced by   Y     of fuels containing carbon.

  1. X - $CO _{2}$, Y = complete combustion
  2. X - $CH _{4}$, Y = incomplete combustion

  3. X = C, Y = oxidation
  4. X = $CH _{4}$, Y = complete combustion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carbon monoxide is basically formed when an object is burned. Methane, which is a natural gas produces  CO after oxidation. Methane, produces less CO as compared to other units of gas. Incomplete combusion results in creation of poisonous CO. It occurs when supply of oxygen is poor. 

Multiple choice chemistry air and water pollution ways to prevent air pollution ways to reduce air pollution reducing air pollution

Incomplete combustion of petrol or diesel oil in automobile engines can be best detected by testing the fuel gases for the presence of __________ .

  1. carbon Monoxide and water vapour

  2. carbon monoxide

  3. nitrogen dioxide

  4. sulphur dioxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The incomplete combustion of petrol and diesel in automobile produces carbon monoxide.

Multiple choice chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

Fire extinguisher's containing $CO _2$ is the best extinguisher.

  1. Because $CO _2$ being heavier than oxygen, covers the fire like a blanket
  2. Because $CO _2$ being heavier than oxygen, increase fire.
  3. Because $CO _2$ being leighter than oxygen, covers the fire like a blanket

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For fires involving electrical equipment and inflammable material like petrol, carbon dioxide is the best extinguisher. Carbon dioxide being heavier than oxygen, covers the fire like a blanket. Since, the contact between the duel and oxygen is cut off, the fire is extinguished.