SO³+HCl

The chemical equation you have mentioned is unclear. It seems to be incomplete, as SO3 and HCl are both compounds and not specific reactants.

However, if you meant to write the balanced chemical equation for the reaction between sulfur trioxide (SO3) and hydrogen chloride (HCl), it can be written as:

SO3 + 2HCl -> H2SO4

This reaction is known as the synthesis of sulfuric acid. In this reaction, sulfur trioxide reacts with hydrogen chloride to produce sulfuric acid (H2SO4).