Question

What is difference between pi and sigma bond and how to recognise them?

Answer 1

A triple bond is one sigma and two pi bonds. Asigma bond is your basic head-on covalent bond, with the bond in line with the bonding orbitals. You can only ever have one sigma bond between any two atoms. A pi bond is a covalent bond between orbitals perpendicular to the bond direction, usually p-orbitals (never s).

you can easily understand when you can see the diagram