[sciencelogic]

For production of dry HCl gas in laboratory methods, mostly I read about dripping of H2SO4 on NaCl with a drying tube containing dehydrated CaCl2 at the escaping neck of the flask. But I read somewhere else that did the dripping of H2SO4 in the solution of HCl and NaCl without using a drying tube.
1. which one of these do you recommend as being the better method and why?
2. Do I really need Lab grade NaCl for using in such a reaction or table salt is good to go?

Thanks.

[chenbeier]

1. It depends what drying grade you need.
2. It depend do you can live with impurities HF, HI, CO2 and others, from table salt.
What is the purpose to use the dry HCl gas?

[sciencelogic]

1. It depends what drying grade you need.
2. It depend do you can live with impurities HF, HI, CO2 and others, from table salt.
What is the purpose to use the dry HCl gas?

So it has impurities, thanks. I'm a newbie and I'm just trying to understand things. I was trying to check the blue litmus paper with HCl gas and HCl solution and in the presence of HCl gas, it changed a little, while it mustn't so I read about  the reason and I understood that it can be either the moisture of the paper or the gas. I dried the paper but still it changed a little, so I thought it might be the gas and I searched about making dry hcl gas. And more than that, I'm curious that, it might be a better choice if the H2SO4 drip in a solution not NaCl crystals, Isn't it?

Thank you

[billnotgatez]

listed on the label
Morton Iodized Salt:  salt, calcium silicate, potassium iodide , and dextrose

a link talking about impurities in salt
https://chemistry.stackexchange.com/questions/24816/how-pure-nacl-is-typical-table-salt-how-is-it-purified

[AWK]

Litmus paper is dipped into the solution, and in the case of gases, the paper is moistened with clean water before use.