What is the symbol equation for the pop test for hydrogen?

That depends on what chemicals were mixed in order to produce the hydrogen gas. For example, if it was the metal magnesium (Mg), and the acid hydrochloric acid (HCl), then the equation would be Mg(s) + 2HCl(aq) -- > MgCl2(aq) + H2(g). Please note that the 2 after MgCl is supposed to be a subscript, as is the 2 after hydrogen. We are having difficulties with the subscripts and superscripts right now.