Question

Write the molecular formula and names of lower and higher homologous of c3h4

Answer 1

C3H4 is the chemical formula of propyne, 
 lower homologue of this compound is ethyne, which has the chemical formula C2H2
HC≡CH

The higher homologue of this compound is butyne, which has the chemical formula C4H6. It has two isomers- But-1-yne which 
HC≡C-CH2-CH3

Answer 2

Each compound in a homologous series differ by a common difference

In this case the given compound is propyne.

Therefore before propyne , comes methyne i.e. C2H2

And after propyne comes butyne i.e. C4H6

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