[Biahbi]

I need to generate anhydrous HCL gas. I know that there are several methods to do this. The most important factor is how dry the gas will be. The second most important factor is keeping the cost down. Dehydraying conc. HCL acid with CaCL2 is the method which appeals to me most. My question is, would the use of a sufficient amount of CaCL2 fully dehyrdate the liquid, releasing the gas, i.e. I won't have to pass the gas through a drying tube or another flask containing conc. sulfuric acid? If the CaCL2 route is not ideal for eliminating all of the water, which method should I use?

[Hunter2]

Better is to create the gas by chemical reaction  PCl₃, PCl₅ and water or melt NaCl and NaHSO₄ together. Dry with phosphorous pent oxide.

[discodermolide]

It's even easier to buy a cylinder.