What is cold Hydrochloric acid?

Answer 1

I'm not quite sure if you've formulated your question correctly.

Hydrochloric acid, HCl(aq), is what it is, whether cold or hot.

When you dilute concentrated HCl the dilution reaction releases

a lot of heat (more of it the more conc. the HCl is to begin with).

Depending on how much you are diluting may cause the reaction

vessel to feel warm (or even hot) to the touch.

When you dilute concentrated HCl you should determine how

much water it will take and then add the HCl slowly to most of the

water required. The water has a high specific heat and can absorb

the heat being generated (but you still add the acid slowly). You

don't add the water to the conc. HCl. The heat generated can be

enough to pretty much instantaneously boil the water and it can

splatter in your face (carrying some of the acid with it) causing a

severe burn.

Answer 2

Sounds like hydrogen chloride that is not dissolved in water.