It is fake. H2O2 is a strong oxidizer and it will oxidize the salt. You will get a yellow solution (chlorinated water). In school you make the same experiment, but at there you use potassium iodide instead of the X-chloride. The reaction goes like this: H2O2 + 2XCl = H2O + X2O + 2ClX2O + 2H2O =2 XOHX can be an alkali metal. So it won't work.