Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: White gas from reaction of HCl with impure CuO?
Hazard to Others

Posts: 185
Registered: 31-1-2020
Location: North-Rhine Westfalia, Germany
Member Is Offline

Mood: Slowly getting ready for new projects

[*] posted on 19-4-2020 at 08:39
White gas from reaction of HCl with impure CuO?

So, I made some not really pure copper powder a few days ago, and yesterday I roasted it to convert it to copper(II)-oxide. I then wanted to convert the copper(II)-oxide into copper(II)-chloride. Thus, I poured some 32% HCl onto the copper oxide. Then, immediately, a white gas or mist came off. In a panic, since I didn't know what this could be, I simply threw in a bit of baking soda to neutralize it.

Does anyone know what this was?

Collected elements:
Al, Cu, Ga, C (coal), S, Zn, Na

Collected compounds:

NaOH; NaHCO3; MnCl2; MnCO3; CuSO4; FeSO4; aq. 30-33% HCl; aq. NaClO; aq. 9,5% ammonia; aq. 94-96% H2SO4; aq. 3% H2O2

citric acid, sodium acetate, sodium citrate, petroleum, mineral oil
View user's profile View All Posts By User
International Hazard

Posts: 949
Registered: 15-4-2019
Location: In Turgon's hidden city
Member Is Offline

Mood: Unavailable

[*] posted on 19-4-2020 at 08:46

It is gaseous HCl. Reaction between conc. HCl and CuO is exothermic and some HCl escaped from solution due to it.

Even when you pour some water in to the conc. HCl, there is some gaseous HCl formation.

[Edited on 19-4-2020 by Bedlasky]
View user's profile View All Posts By User
Hazard to Self

Posts: 70
Registered: 24-8-2019
Location: Kansas, USA
Member Is Offline

Mood: brøthér, can you spare some B̲̺̹̙̑́̓́ͧ̎ͭ̈́͜L̰̦̼̻͈͖̺͔̇̇̿ͪ̓̃̽ͦŲ̘̲̻͔̀͌͑͑̊͛̑̀͊̕E̐ͮͯ͆̔̾͘͏҉̥̫

[*] posted on 19-4-2020 at 09:40

That, and 32% is well above the point where HCl fumes, reaction or not. But theoretically the reaction of HCl and CuO is a double displacement reaction that would gives off H2O, some of which would be released as steam if it gets hot enough.
View user's profile View All Posts By User
National Hazard

Posts: 454
Registered: 26-10-2017
Location: Poland
Member Is Offline

Mood: Psychedelic

[*] posted on 19-4-2020 at 10:51

Hydrochloric acid tends to fume at even lower concentrations and especially during reactions with something.
Yesterday, when I poured crude mother liquor from propiophenone synthesis into hydrochloric acid, it created so big cloud of HCl that it burned my hands and it was technical grade 31%.
Reason why HCl vapors are white, is that the gas is "damp" it contains water vapors maybe even something steam - like in it, which make it appear white.
View user's profile View All Posts By User

  Go To Top