\(\left(1\right)CaC_2+2H_2O--->C_2H_2+Ca\left(OH\right)_2\)
\(\left(2\right)C_2H_2+H_2\xrightarrow[Ni]{t^o}C_2H_4\)
\(\left(3\right)C_2H_4+Br_2--->C_2H_4Br_2\)
\(\left(4\right)C_2H_4+3O_2\overset{t^o}{--->}2CO_2\uparrow+2H_2O\)
\(\left(5\right)CO_2+Ca\left(OH\right)_2--->CaCO_3\downarrow+H_2O\)