Question

What is the general formula that represents the compound `CH_3CH_2C CH`?

Answer 1

`"R"_1-"C"-="C"-"R"_2`, I suppose, since this is an alkyne, a hydrocarbon with a triple bond (and a pure alkyne has no double bond).

From the single `"H"` on the far right, the far-right carbon must be `sp`-hybridized. It has two `sigma` bonds, one with that right-hand `"H"` and one with the next to last carbon.

Structurally...

`"H"_3"C"-"CH"_2-"C"-="C"-"H"`

Can you rationalize why this compound is called 1-butyne?

Answer 2

`"HC"-="CCH"_2"CH"_3` is `"1-butyne"`.

Explanation:

`"Butyne"`, `C_4H_6` has 2 degrees of unsaturation with respect to saturated `"butane"`, `C_4H_10`.