What is the reaction between Argon with either HCl or H2SO4?

There isn't. Argon is one of the “inert” or noble gases, and it lives up to its reputation. No normal reactions in the ground state even with the incredibly reactive difluorine . read more

There isn’t. Argon is one of the “inert” or noble gases, and it lives up to its reputation. No normal reactions in the ground state even with the incredibly reactive difluorine . In electrical discharges with halogens you can get excited state argon compounds such as ArF*, which emits light in the harder UV at 193 nm. read more

The only thing that I can come up with is that you may have added dilute HCl to concentrated H2SO4, effectively diluting the H2SO4 with the water in the dilute HCl. Diluting concentrated H2SO4 produces a lot of heat, maybe that was what you saw. read more