Answer:
IHD = 0
Explanation:
Given that
C₆H₁₅N
Number of carbon atoms(n) = 6
Number of hydrogen atoms(x') = 15
Number of nitrogen atoms = 1
There is nitrogen atoms then x = x' -1
The index of hydrogen deficiency given as

So


IHD = 0
The index of hydrogen deficiency is zero.
Epsilon-delta would be the green letter that is used in the precision definition of a limit. (ε, δ).
It will be:
b. Alkyne* series
* You have done a spelling mistake here. It will be "Alkene" not "Alkyne".