The number isomeric alkynes possible with the formula C₆H₁₀ are

DBE=C+1−H/2−X/2+N/2
Where,
C = Number of carbon atoms present in organic molecules.
H = Number of hydrogen atoms present in organic molecules.
X = Number of halogen atoms present in organic molecules.
N = Number of nitrogen atoms present in organic molecules.

DBE  of  C₆H₁₀ =C+1−H/2

                 = 6+ 1- 10/2

                   = 2

Structure VI containing stereo center which has two isomers ,total no. of isomers are 8