Homework 1.5c

[Aimiel Casillan 1J]

Homework problem 1.5c in the Introduction to Organic Chem textbook asks for the molecular formula and hydrocarbon type of the following organic molecule:

I understand why the molecule is an alkyne (because it has a triple bond), but I don't understand why its formula is . Please help!

[Bryce Bentley 1l]

The formula for alkynes is C(n)H(2n-2) n is the number of carbon atoms. So for propyne it is C(3)H(2*3-2) which comes out to C3H4.

[Reine Nakamura 1C]

I wondered the same thing! It helps to draw in where the C atoms are and fill in the H atoms so that each C has 4 bonds... By doing this, it's easier to see that the formula is C₂H_2n-2, and in this case, C₃H₄.