1) Why use this method? Because it was supposedly cleaner, with no blood?
2) Why did they use Zyklon B? There are plenty of poisonous gases out there, is Zyklon B special in any way?
3) How many people are claimed to have been killed in gas chambers?
4) How did these gas chambers work? How common were they? Did other prisoners know about them?
Hopefully I can get some (documented) sources for these questions. I don't care if they come from deniers, affirmers, or revisionists. I just want to know what actually happened.
1, The Germans switched from mass shooting to gassing as the primary mode of murder because mass shootings (of women, kids, etc) were too psychologically burdensome on the SS killers. Gassing was a more impersonal method.
2. Zyklon B was abundant in the camps (for delousing purposes) and hydrogen cyanide is highly lethal to human beings, so it makes sense that they would use it. At Auschwitz, the Nazis first starting using Zyklon-B experimentally as a means of killing Soviet POWs (who were also subject to genocide by the Nazis).
3. The best estimate I could give you for gassed Jews is about 2.7 million. This includes about 1 million in Auschwitz (via Zyklon B, in the 5 cremas and the two bunkers), about 1.4 million in the gas chambers of Sobibor, Belzec, and Treblinka (via petrol exhaust); about 150,000 in Kulhomf (via petrol exhaust); about 50,000 in Majdanek (via Zyklon B); about 50,000 in Maly Trostinets (via petrol exhaust); and many thousands more in other locations.
The total Jewish death toll exceeds 5 million. This figure not only includes gassing and other deaths at camps, but mass shootings (by the Germans, the Romanians, the Croats, and local collaborators), starvation, and overwork.
4. Exposure to Hydrogen cyanide (Auschwitz gas chamber) and carbon monoxide (Aktion Reinhardt gas chambers) at certain concentrations is lethal to human beings. The gas chambers were simply enclosed and sealed rooms that had a means of introducing HCN and carbon monoxide gas inside (e.g. holes/wire-mess columns in the roof of crematoria 2 and 3; a piping system at a Treblinka gas chamber). Not very hard to imagine how this process could kill people if you know or read some very basic chemistry.