what is number of sigma and pi bond in c2(cabon molecule)

Firstly carbon do not form quadruple bond.because•absence of d orbital makes excitation of electrons impossible•according to VBT ,no sufficient p orbital in required orientation•if it forms also it is unstable due to high repulsion arising from high electron density.further to answer your question if i assume suuh a hypothetic molecule then●any molecule can form only one sigma bond. So 1 sigma btwn C2●remaining 3 pi bond btwn C2

It is an exception that in C2 molecule both the bonds are pi bonds.And this can be explained by MOT the last four elctrons go in the bonding molecular π2PX-π2PY orbital hence the bond formed are pi.