Question

In acetylene, there are ______ (two/four) $\pi$ - bonding electrons between carbon atoms.

Answer 1

The structure of Acetylene is: $(CH\equiv CH)$

It contains two $\pi$ -bonds and each $\pi$ - bond contains two $\pi$ bonding electrons. So a total of four $\pi$ bonding electrons are present in acetylene.

So, the correct answer is 4.