Question

balanced equation of (C2H2)

Answer 1

it's combustion equation or another?

Answer 2

If we're talking about the complete combustion of acetylene, then it's:
2 C2H2 + 5 O2 → 4 CO2 + 2 H2O

If we're talking about the production of acetylene, the common method is:
CaC2 + 2 H2O → Ca(OH)2 + C2H2