Content Writer
A hydrocarbon is an organic compound composed entirely of hydrogen and carbon. The simplest form of these compounds is a saturated hydrocarbon, which tends to have all carbon atoms bonded with a single bond and is entirely saturated with hydrogen atoms.
- A saturated hydrocarbon consists of a maximum number of hydrogen atoms for the number of carbon atoms.
- These types of hydrocarbons do not form any multiple bonds.
- Saturated hydrocarbons are also known as alkanes.
- In this compound, each carbon atom completes its valency by linking with four other atoms, thus forming single bonds.
- The word saturated is derived from the Latin word saturare, which means 'to fill'.
- The general formula of saturated hydrocarbons is CnH2n+2 where n is the number of carbon atoms.
Key Terms: Hydrogen, Hydrocarbon, Saturated Hydrocarbon, Carbon, Organic Compound, Atoms, Single Bond, Alkane, Unsaturated Hydrocarbon, Types of Saturated Hydrocarbon, Uses of Saturated Hydrocarbon
Saturated Hydrocarbon
[Click Here for Sample Questions]
A saturated hydrocarbon is an organic compound that contains only hydrogen and carbon that contain only single bonds between the atoms. In general, the term is most used to denote acyclic hydrocarbons also known as alkanes.
- In a saturated hydrocarbon, all the carbon atoms are bonded to four other atoms, generally to as many hydrogen atoms as possible and hence ‘saturated’.
- There is no presence of multiple bonds between carbon atoms in these compounds.
- They contain only sp3 hybridized carbon atoms and their general formula is CnH2n+2.
- The general formula of saturated hydrocarbon is CnH2n+2(1-r), where ‘r’ is the total number of rings in the molecule.
- Cycloalkanes are the alkanes that have one ring i.e. a monocyclic ring structure.
- The structure of these compounds is a ring-like structure instead of a linear structure.
- They are named analogously to their normal alkane counterparts of the same carbon count.
Saturated Hydrocarbon ExamplesExample: Some of the examples of this type of compound are- Ethane (C2H6), Propane (C3H8), Butane (C4H10), and Octane (C8H18). |
Read more:
| Chapter Related Concepts | ||
|---|---|---|
| Avogadro’s Number | Valence Electrons | What is partial Pressure |
Properties of Saturated Hydrocarbon
[Click Here for Sample Questions]
The important characteristics of saturated hydrocarbon are as follows:
- Saturated hydrocarbons have a linear or branched chain structure.
- They consist of single covalent bonds between carbon atoms.
- These hydrocarbons have low reactivity, as their carbon-carbon bonds between atoms are stable.
- Saturated hydrocarbons have a high boiling point due to strong intermolecular forces of attraction between molecules.
- These compounds are insoluble in water.
- They are non-polar in nature due to the symmetrical distribution of electrons.
Difference between Saturated and Unsaturated Hydrocarbon
[Click Here for Sample Questions]
The key differences between saturated and unsaturated hydrocarbons are mentioned below -
| Saturated Hydrocarbon | Unsaturated Hydrocarbon |
|---|---|
| In these compounds, all the carbon atoms are sp3 hybridized. | These compounds have either sp or sp2 hybridized carbon atoms |
| They have single bonds between the carbon atoms. | There is at least one double or triple bond between carbon atoms. |
| These compounds are generally less chemically reactive in nature. | These compounds are more reactive than their saturated counterparts. |
| They contain more hydrogen atoms per carbon atom. | They contain comparatively fewer hydrogen atoms per carbon atom. |
| It generally burns with a blue flame. | It usually burns with a sooty flame. |
| Saturated hydrocarbon is more stable. | Unsaturated hydrocarbon is less stable. |
| These do not undergo polymerization. | These undergo polymerization. |
| They do not have any pi bonds between carbon atoms. | They have pi bonds between carbon atoms: one pi bond in alkenes, two pi bonds in alkynes. |
| These compounds undergo substitution reactions. | These compounds undergo addition reactions. |
| It includes alkanes and cycloalkanes. | It includes alkenes, alkynes, and aromatic compounds. |
| Saturated hydrocarbon has a high melting point. | Unsaturated hydrocarbon has a low melting point. |
| Example- Methane | Example- Benzene |
Types of Saturated Hydrocarbons
[Click Here for Sample Questions]
A saturated hydrocarbon compound can form linear, branched, or ring-shaped cyclical structures. On the basis of their structure, they are mainly classified into two groups-
Alkanes
In organic chemistry, an acyclic saturated hydrocarbon is called alkane or paraffin. They can form a tree-like linear or branched carbon chain structure. All alkanes are colourless in their natural state.
- The melting point of these compounds is directly proportional to the length of the carbon chain.
- The more carbon atoms an alkane has, the more molecular weight the specific compound has, and consequently, the boiling point rises.
- At a standard room temperature, compounds containing up to four carbon atoms are gases.
- Alkanes containing 5 to 17 carbon atoms are liquids, and those with more than 18 carbon atoms are solids.
- Typically, the solid alkanes are all waxes.
- The main sources of alkanes are petroleum (crude oil) and natural gas.
Cycloalkanes
In organic chemistry, the monocyclic saturated hydrocarbons are called cycloalkanes or naphthenes. These compounds are named analogously to their normal alkane counterparts of the same carbon count.
- A cycloalkane features a ring-like structure with side chains.
- The larger of these compounds have more than 20 carbon atoms, which are called cycloparaffins.
- The simpler version of the formula of the cycloalkane that is used is CnH2(n).
- These compounds have the same number of carbon atoms as their alkane counterpart.
- Cycloalkanes are also denser than alkanes
- They have higher boiling and melting points than those alkanes.
The cycloalkane compounds which does not have any side chains are classified into – small (cyclopropane and cyclobutane), common (cyclopentane, cyclohexane, and cycloheptane), medium (cyclooctane through cyclotetradecane), and large (all the rest).
Cycloalkanes
Uses of Saturated Hydrocarbons
[Click Here for Sample Questions]
There are several use of saturated hydrocarbons. In modern-day applications, it is primarily used as a source of fuel. Some of the main uses are as follows –
- Highly refined methane is used as liquid rocket fuel.
- In its simplest form methane gas can be used as a fuel for automobiles, water heaters, and ovens.
- Saturated hydrocarbons are predominantly used as a combustible fuel source.
- Alkanes and cycloalkanes are the top components of gasoline, naphtha, jet fuel, and specialized industrial solvent mixtures.
- Ethane is used as a refrigerant in several cryogenic refrigeration systems.
- It is also used to produce ethylene gas.
- Propane is used as the propellant in several aerosol sprays and also as fuel in hot air balloons.
- It is also used in the production of propylene gas.
- Butane is used as fuel for lighters, portable stoves, camp heaters, and canister torches.
- It is also used as a propellant for deodorants.
- Octane is mostly mixed with gasoline to prevent engine damage.
- Cycloalkanes are mainly used in motor fuels, diesel, petroleum gas, and other heavy oils.
- They are also used in manufacturing rubber and nylon.
- It is also used as roofing compounds, pavement composition (bitumen), wood preservatives, and as extremely high viscosity shear-resisting liquids.
Also Read:
| Related Articles | |||
|---|---|---|---|
| Hydrogen | Organic Solvents | Isotopes of Hydrogen | |
| Types of Redox Reactions | Green Chemistry | Redox Reactions | |
Things to Remember
- A hydrocarbon is an organic compound that consists of only hydrogen and carbon.
- Saturated hydrocarbons are compounds in which all carbon atoms are bonded with single bonds.
- They are used to denote acyclic hydrocarbons, also known as alkanes.
- The major difference between saturated and unsaturated hydrocarbons is that carbon atoms are bonded with a single bond in saturated hydrocarbons.
- In contrast, carbon atoms are bonded with at least one double or triple bond in unsaturated hydrocarbons.
- They are found in linear, branched, or ring-shaped cyclic structures.
Sample Questions
Ques: Classify the hydrocarbons according to the carbon-carbon bond? (2 marks)
Ans: Hydrocarbons are classified into three categories according to the carbon-carbon bond that exists between them. The types of hydrocarbons are as follows:
- Saturated hydrocarbon
- Unsaturated hydrocarbon
- Aromatic hydrocarbon.
Ques: What are cycloalkanes? (1 mark)
Ans: Cycloalkanes are compounds in which carbon atoms are present in a closed chain or a ring.
Ques: The boiling point of alkanes show a steady increase with an increase in molecular mass. Why? (1 mark)
Ans: The boiling point of alkane shows a steady increase because the intermolecular van der walls forces increase with an increase in the molecular size or the surface area of the molecule.
Ques: Why are alkanes called paraffins? (1 mark)
Ans: Paraffins are compounds that have very less affinity. Alkanes due to strong C-C and C-H bonds are chemically inert and have less affinity.
Ques: How many types of saturated hydrocarbons can be found easily? (2 marks)
Ans: On the basis of their structure, saturated hydrocarbons are classified into two types. They are-
- Alkanes
- Cycloalkanes
Ques: (a) Write structures of different chain isomers of alkanes corresponding to the molecular formula C6H14. Also, write their I.U.P.A.C. names.
(b) Write structures of different isomeric alkyl groups corresponding to the molecular formula C5H11. Write IUPAC names of alcohols obtained by attachment of -OH groups at different carbons of the chain? (3 marks)
Ans: (a) Isomers of C6H14
(b) Structures of Corresponding alcohols of C5H11 group
Ques: What are the hydrocarbons write the name and general formula of (i) saturated hydrocarbons, (ii) unsaturated hydrocarbons, and draw the structure of one hydrocarbon of each type. How can an unsaturated hydrocarbon be made saturated? (3 marks)
Ans: (i) Alkanes are saturated hydrocarbons.
(ii) Alkenes and Alkynes are unsaturated hydrocarbons.
Ques: (a) Give a chemical test to distinguish between saturated and unsaturated hydrocarbons.
(b) (i) Name the products formed when ethanol burns in the air. ‘
(ii) What two forms of energy are liberated on burning alcohol?
(c) Why is the reaction between methane and chlorine considered a substitution
reaction? (3 marks)
Ans: (a) Bromine Water- On adding bromine water, saturated hydrocarbons do not react whereas unsaturated hydrocarbons decolourise on adding bromine water.
(b) (i) CO2 and H2O
C2H5OH (l) + 3O2 (h) → 2CO2 (g) + 3H2O (l) + Heat + Light
(ii) Heat energy and light energy are liberated on burning the alcohol.
(c) The reaction between methane and chlorine is considered a substitution
CH4 (g) (Methane) + Cl2 (g) (Chlorine) → CH3Cl(g) (Chloromethane) + HCl (g)
Reaction because ‘Cl’ atom substitutes ‘H’ atom of methane to form chloromethane and hydrogen chloride.
Ques: Write any three uses of Saturated Hydrocarbons? (3 marks)
Ans: The uses of Saturated Hydrocarbons are mentioned below:
- Highly refined methane is used as liquid rocket fuel and methane gas can be used as a fuel for automobiles, water heaters, and ovens.
- Saturated hydrocarbons are predominantly used as a combustible fuel source.
- Alkanes and cycloalkanes are the top components of gasoline, naphtha, jet fuel, and specialized industrial solvent mixtures.
Ques: Why alkanes are known as saturated hydrocarbons? (2 marks)
Ans: Each alkane molecule's four valencies are joined by single covalent bonds to either carbon atoms, hydrogen atoms, or both, demonstrating that the alkane's carbon skeleton is fully saturated. Alkanes are hence referred to as saturated hydrocarbons.
Ques: How can we prepare alkane? (3 marks)
Ans: Saturated hydrocarbons are known as alkanes. Alkenes and alkynes are simply prepared for them. This is where the hydrogenation process takes place. To expedite the process, dihydrogen gas is passed across a metal surface with the presence of catalysts like nickel. They transform into alkanes when they come into contact with the alkenes and alkynes. Alkyl halides can even be used to produce alkanes such as propane, butane, and ethane.
Also Read:
Comments