To get C2H2 from CH3Cl, you need to follow these steps:

First, react CH3Cl with Na metal to form ethyl chloride (C2H5Cl) and sodium chloride (NaCl) according to the reaction:
2CH3Cl + 2Na -> C2H5Cl + 2NaCl

Then, heat ethyl chloride (C2H5Cl) in the presence of a strong base like KOH to get C2H2 and ethanol (C2H5OH) through dehydrohalogenation reaction:
C2H5Cl + KOH -> C2H2 + C2H5OH + KCl

Thus, by reacting CH3Cl with Na metal and then heating the resulting ethyl chloride with KOH, you can obtain C2H2 from CH3Cl.