The 5\(^{th}\) member of an alkyne series is

Question 1 Report

C\(_5\)H\(_8\)

C\(_5\)H\(_{10}\)

C\(_6\)H\(_{12}\)

C\(_6\)H\(_{10}\)

Answer Details

The alkynes are a homologous series of unsaturated hydrocarbons containing a carbon-carbon triple bond. Their general formula is:

\[\text{C}_n\text{H}_{2n-2}\]

The series begins at \(n = 2\) (since at least two carbon atoms are needed to form a triple bond):

Member	n	Formula	Name
1st	2	C₂H₂	Ethyne
2nd	3	C₃H₄	Propyne
3rd	4	C₄H₆	Butyne
4th	5	C₅H₈	Pentyne
5th	6	C₆H₁₀	Hexyne

The 5th member has \(n = 6\): \(\text{C}_6\text{H}_{2(6)-2} = \text{C}_6\text{H}_{10}\).

C₅H₈ is the 4th member, not the 5th. C₅H₁₀ and C₆H₁₂ fit the alkene general formula (C_nH_2n), not the alkyne formula.

Related Questions