How can you tell if something is alkane or alkene?

Asked By: Rehab De Burgos | Last Updated: 16th March, 2020
Category: science chemistry
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A simple test with bromine water can be used to tell the difference between an alkane and an alkene. An alkene will turn brown bromine water colourless as the bromine reacts with the carbon-carbon double bond. In fact this reaction will occur for unsaturated compounds containing carbon-carbon double bonds.

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Just so, how can you distinguish between alkenes and alkyne?

Key Takeaways

  1. Alkenes and alkynes are named by identifying the longest chain that contains the double or triple bond.
  2. The chain is numbered to minimize the numbers assigned to the double or triple bond.
  3. The suffix of the compound is “-ene” for an alkene or “-yne” for an alkyne.

Also, what two solutions can we use to test for alkenes? This allows us to tell alkenes apart from alkanes using a simple chemical test. Bromine water is an orange solution of bromine. It becomes colourless when it is shaken with an alkene. Alkenes can decolourise bromine water, but alkanes cannot.

Considering this, is alkane or alkene more reactive?

Alkenes are relatively stable compounds, but are more reactive than alkanes because of the reactivity of the carbon–carbon π-bond. Most reactions of alkenes involve additions to this π bond, forming new single bonds.

How can you distinguish between alkane alkene and alkyne?

Alkanes are saturated hydrocarbons; meaning a single bond between the carbon atoms; alkenes are unsaturated hydrocarbons meaning one or more double bonds between carbon atoms; alkynes are also unsaturated hydrocarbons with one or more triple bonds between the carbon atoms.

29 Related Question Answers Found

How do you distinguish between ethyne and ethene?

The main difference between Ethene and Ethyne is that Ethene is composed of sp2 hybridized carbon atoms whereas Ethyne is composed of sp hybridized carbon atoms.

How do you test for alkynes?

Unsaturated hydrocarbons such as alkenes and alkynes are much more reactive than the parent alkanes. They react rapidly with bromine, for example, to add a Br2 molecule across the C=C double bond. This reaction provides a way to test for alkenes or alkynes. Solutions of bromine in CCl4 have an intense red-orange color.

How are alkenes produced?

Alkenes are produced by hydrocarbon cracking. Alkanes are broken apart at high temperatures, often in the presence of a zeolite catalyst, to produce a mixture of primarily aliphatic alkenes and lower molecular weight alkanes. The mixture is feedstock and temperature dependent, and separated by fractional distillation.

What does an alkyne look like?

In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. Like other hydrocarbons, alkynes are generally hydrophobic but tend to be more reactive.

Are alkanes polar or nonpolar?

Alkanes are non-polar solvents. Since only C and H atoms are present, alkanes are nonpolar. Alkanes are immiscible in water but freely miscible in other non-polar solvents. Alkanes consisting of weak dipole dipole bonds can not break the strong hydrogen bond between water molecules hence it is not miscible in water.

Are alkenes soluble in water?

Solubility. Alkenes are virtually insoluble in water, but dissolve in organic solvents. The reasons for this are exactly the same as for the alkanes.

Are alkanes soluble in water?

Solubility. Alkanes (both alkanes and cycloalkanes) are virtually insoluble in water, but dissolve in organic solvents. However, liquid alkanes are good solvents for many other non-ionic organic compounds.

Where do we get alkanes from?

Occurrence of alkanes on Earth
The most important commercial sources for alkanes are natural gas and oil. Natural gas contains primarily methane and ethane, with some propane and butane: oil is a mixture of liquid alkanes and other hydrocarbons.

Are alkenes more reactive?

Yes, alkenes are more reactive. This is due to the properties of the carbon-carbon bond. In alkanes there is a single bond, denoted as . At first thought, it seems that double must be stronger than single but in fact, due to the nature of the bond, it is more reactive than a -bond.

Are alkynes or alkenes more reactive?

(a) Alkynes are more reactive than alkenes because alkynes have two π bonds between carbon-carbon triple bond. Thus more number of electrons are available than the electrons present in alkenes carbon-carbon double bond. This will make the alkynes undergo for more reactive.

Why are alkanes not very reactive?

Alkanes are not very reactive when compared with other chemical species. This is because the backbone carbon atoms in alkanes have attained their octet of electrons through forming four covalent bonds (the maximum allowed number of bonds under the octet rule; which is why carbon's valence number is 4).

Why are alkanes called paraffins?

Paraffins is a Latin word meaning (parum = little + affinis = reactivity). Alkanes are called paraffins because they have a little affinity towards a general reagent. In other words,alkanes are inert substances. They undergo reactions under drastic conditions.

Is benzene more reactive than alkenes?

Question: Alkenes Are More Reactive Than Benzene And Undergo Addition Reactions, Such As Decolourizing Bromine Water In Reaction (A) Below, In Which The C=C Double Bond Is Lost. Benzene Only Reacts With Br_2 In The Presence Of A Catalyst And The Product Only Contains One Br Atom And The Benzene Ring Remains Intact.

Why are alkenes not used as fuels?

Alkenes are not used as fuels because: They are scarce in nature. They are made from other hydrocarbons to make plastics, anti–freeze and many other useful compounds. They burn with a smoky flame due to less efficient, and more polluting incomplete combustion, so the heat energy release is lower than for alkanes.

Are alkanes reactive?

Alkanes are generally unreactive. Alkanes contain strong carbon-carbon single bonds and strong carbon-hydrogen bonds. Alkanes can be burned, destroying the entire molecule, alkanes can react with some of the halogens, breaking carbon-hydrogen bonds, and alkanes can crack by breaking the carbon-carbon bonds.

What is the test for unsaturation?

In organic chemistry, the bromine test is a qualitative test for the presence of unsaturation (carbon-to-carbon double or triple bonds), phenols and anilines. The more unsaturated an unknown is, the more bromine it reacts with, and the less coloured the solution will appear.