equipment to stop suckback when using hcl gas

[mithyl2]

what equipment should be used to stop suckback when gassing a solution with hcl gas?

 

[PNicole]

Use a 3-Way Stopcock (glass) and you can also equip your tubing with quick disconnects (Bel-Art makes good ones) in case of emergencies. The danger of suckback happens when you have stopped adding HCl to sulfuric acid yet it is still bubbling so you keep the exit tube in the liquid. If you pull the tube out of the solvent there will still be some gas escaping which is not good for anyone. So after the HCl drip is stopped, I will wait a minute or less and then turn the stopcock to direct the gas into a Erlenmeyer with chilled IPA. The IPA filled flask is the lowest point of the setup. Use quick disconnects to then unhook tubes if you are also worried about leaving in liquid too long.

 

[mithyl2]

but might the gas generating flask explode if i block the outlet for it using the 3 way stopcock? even if only a small amount of gas is evolving from it

 

[testint]

Gas with a upside down funnel

 

[mithyl2]

do you mean the end of the hose that is in the solution being gassed should have an upside down funnel attached to it?

 

[testint]

Yes there are better ways but that always worked well for me. My guess is by increasing the surface area the gassing process is very rapid due to surface area and has the added effect of a funnel trap.

 

[mithyl2]

thanks i'll try it out