Aliphatic Compound

What is Aliphatic Hydrocarbon?

Aliphatic Hydrocarbon Meaning - Aliphatic usually implies an aliphatic compound, meaning an organic compound in which the atoms are bound by single, double, or triple bonds to form nonaromatic structures. The alkenes, alkynes, and alkanes, as well as the substances extracted from them - directly or in theory - by replacing one or more hydrogen atoms with atoms from other groups of atoms or elements, make up the main structural groups of organic molecules known as aliphatic compounds. In this way, we can give the aliphatic compounds meaning.


Aliphatic compounds can be either saturated (alkanes) or unsaturated (alkenes) with single or double bonds (alkenes) or triple bonds (alkenes) (alkynes). Other elements, in addition to hydrogen, can be bound to the carbon chain, the most common of which are oxygen, nitrogen, sulphur, and chlorine. Whereas, aliphatic carbon (hydrocarbon) are organic chemicals.

The least complex of all aliphatic compounds is methane (CH4).

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Tests to Identify Aromatic and Aliphatic Compounds

  • Ultraviolet radiation is blocked by aromatic compounds. The majority of aliphatic compounds do not absorb UV radiation, but those with three or more conjugated double bonds do.

  • Assuming that the aromatic ring contains an H atom, which is attached to it, we can find the resonance of proton NMR around 7 ppm. Aliphatic compounds will not have a peak in that specific area.

  • Also, there are some differences in the IR spectrum as well.

  • The elemental analysis will also give a clue, as:

A benzene ring = 4 unsaturation degrees = eight “missing” hydrogen atoms, which are relative to a saturated compound.

However, there are some other ways to get 4 degrees of unsaturation (for example, two triple bonds).

Difference Between Aromatic and Aliphatic Compounds

Let us look at the difference between aromatic and aliphatic hydrocarbons meaning with various parameters as tabulated below.


Aromatic Compounds

Aliphatic Compounds

Flame Test

When burnt, it produces a sooty flame

When burnt, it won’t produce a sooty flame


Pleasant odour

Unpleasant odour


The carbon compounds linking occurs in the ring structure using conjugated pi electrons

The carbon compounds linking occurs in a straight line manner


Benzene, naphthalene

Butane, propane

Steps to Determine the More Reactive Compound

The chemical reactivity of the substance is based upon its thermodynamic stability. All the chemical reactions involve existing bonds breaking and making new ones, mostly by the release of excess energy in the heat form. It is also said that the greater the thermodynamic stability of the substance, the lower will be the tendency of it to undergo a chemical change.

An important thermodynamic parameter to define the stability is its standard enthalpy of formation. Let us discuss comparing the standard enthalpy of formation (in kJ/mol) of the hydrogen halides:

HCl -92.3

HF -273.3

HI +26.5

HBr -36.3

The more negative the formation enthalpy, the greater will be the stability of the compound formed. Also, the lower will be its tendency to react in a given specific environment.

The regular reactive nature of the hydrogen halides will be increased in the order HF < HCl < HBr < HI, and their respective thermodynamic stability will be decreased in the order HF > HCl > HBr > HI.

Most Reactive Metal

Probably Lithium is given as the most reactive metal. But, it is a generalization simply because we have to specify the one it is going to react with. There are several reactive metals such as Sodium, Lithium, Aluminum, Cesium, Potassium, Calcium, Magnesium, and others. The ones such as Aluminum might appear quite nonreactive at first, but if it is finely powdered and the surface oxide coating is removed, then it will be as in the reactive mode. 

If we think about the energy released in a Thermite reaction, it is enough to melt and weld together two large volumes of railway tracks, or the solid rocket boosters, which are used to boost the vehicles into orbit, or in the military flash-bang, there is plenty of power in Aluminum. Again, the soft metals such as potassium and sodium literally explode if thrown into the water or any other similar liquid, and a piece, which is the size of a tennis ball, is thrown into a lake; it gives us one hell of a scare.

Then, let us discuss what do we mean by reactive? What about the two pieces of Plutonium 239 or Uranium 235? Bring together two pieces of a certain weight, and we will no longer be around. Those particular smaller pieces are emitting trillions and trillions of the fast-moving Neutrons, which are why those pieces are a little warm in our hands, and if we have enough of the stuff at one place, then those particular neutrons contain a nasty habit of building up more and more neutrons by the process of colliding with the atoms, releasing even MORE of them, in a cumulative runaway process of cascading, a chain reaction, which spreads in less than a microsecond, bombarding those atoms, so, they split into the smaller parts, and releases energy in that process.

So, that is the other form of reactivity, but not the chemical reactivity, which is simply the atom’s electrons, but nuclear reactivity, which is the protons, neutrons, and nucleus. This is where the huge majority of all the energy of matter is found. So we can see that it entirely depends on what we mean by saying reactive and in what way the reactive is? And with what it is reactive? and more.

FAQs (Frequently Asked Questions)

Q1. Give the Properties of Aliphatic Compounds?

Answer: The most significant characteristic of the aliphatic compounds is, most of them are flammable compounds. Due to this reason, these compounds are often used as fuels. A few of the examples of aliphatic fuels are acetylene, methane, and Liquefied Natural Gas (LNG).

Q2. Give Examples of Aliphatic Compounds.

Answer: A few of the examples of Aliphatic Compounds are given as isooctane, Ethylene, propene, propane, acetylene, polyethylene, and squalene. At the same time, the simplest aliphatic compound is given as methane, CH₄.

Q3. Define Aliphatic Compounds.

Answer: Open-chain compounds that have none of the rings are given as aliphatic, whether they have single, double, or triple bonds. In other terms, they can be either saturated or unsaturated. A few aliphatics are cyclic molecules, but their rings are the ones that are not as stable as those of the aromatic compounds. While hydrogen atoms are the most commonly bound ones to the carbon chain, nitrogen, oxygen, chlorine, or sulfur atoms might also be present.

Q4. What are Aromatic Compounds?

Answer: Aromatic compounds are the same as aliphatic compounds, which means that they are both made of carbon. However, they are also much different from one another in other ways. An aromatic organic compound can be characterized by the fact that they have both a ring structure and an alternating double-single-double-single bond network all around the ring. Benzene is one of the most common examples of an aromatic compound.