Question

How can you name the hydrocarbon group based on the number of carbon atoms? Support your answers with examples?

Answer 1

So hydrocarbon are the compounds containing Carbon and hydrogen mainly so if we consider normal hydrocarbon group which is Alkane so in Alkane we have all the carbon and hydrogen are single bonded there is no site of unsaturation or presence of double bond.

So general formula for Alkane is C_{​​​​​​n}​​​​​H_​2n+2.

Let's take an simple example the smallest Alkane is CH_{​​​​​4}​​​​ so it has one carbon and 4 hydrogen are attached to it.

So it is called as methane so there is a homologous series made up from methane as ethane (C2H6), propane (C3H8) , butane (C4H10) and so on so this is Alkane so the name ends with -ane

Next class is alkene where there is one site of unsaturation so it is CnH2n where there is one double bond is present or we can say there is one site of unsaturation so they are named as ethene (C2H4), propene (C3H6) etc.

Then comes alkyne where we have general formula as CnH2n-2 so here there is one triple bond is present so for example ethyne (C2H2), Propyne (C3H4) etc.

More examples as shown below;