Question

Study and complete the following table:

Homologous series	Alkane	Alkyne
General formula	CnH2n+2	1. ______
IUPAC name	2. ______	Ethyne
Common name	Marsh gas	3. ______

Answer 1

Homologous series	Alkane	Alkyne
General formula	CnH2n+2	1. CnH2n−2
IUPAC name	2. Methane	Ethyne
Common name	Marsh gas	3. Acetylene

Explanation:

1. The general formula of the alkyne is C_nH_2n−2· Due to the presence of triple bond four hydrogens are removed from the molecular formula of alkane. For example, in the case of ethyne, the two carbons have already formed triple bonds therefore they only need one more bond in order to complete their octet.

2. The IUPAC name of the first member of the alkane family is methane. Also, the common name given in the table is Marsh gas which is the common name of methane gas.

3. The common name of ethyne is acetylene as it contains the acetyl group. This name was coined by a French chemist (Marcelin-Pierre-Eugene Berthelot) in 1864.