The alkynes are straight-chain hydrocarbons
with one triple bond per molecule

ethyne	C2H2	CH2CH2
propyne	C3H4	CHCCH3
but-1-yne	C4H6	CHCCH2CH3
pent-1-yne	C5H8	CHCCH2CH2CH3
hex-1-yne	C6H10	CHCCH2CH2CH2CH3
hept-1-yne	C7H12	CHCCH2CH2CH2CH2CH3
oct-1-yne	C8H14	CHCCH2CH2CH2CH2CH2CH3
non-1-yne	C9H16	CHCCH2CH2CH2CH2CH2CH2CH3
dec-1-yne	C10H18	CHCCH2CH2CH2CH2CH2CH2CH2CH3

Sometimes long chain formulas are abbreviated
e.g. CHCCH₂CH₂CH₂CH₂CH₂CH₃ may be written CHC(CH₂)₅CH₃
The general formula of the alkynes is: C_nH_2n-2