if solvents are not thoroughly wiped off of base metals, what hazardous gas can form during welding…

Brief Explanations:

Phosgene gas is a highly toxic gas that can be formed during welding operations if solvents are not thoroughly wiped off of base metals. Nitrogen gas, argon gas, and oxygen gas do not form phosgene under such circumstances. Nitrogen and argon are inert gases (argon is a noble gas), and oxygen is a common element in the air but does not react with solvents in this way to produce phosgene. Phosgene (COCl₂) can be formed from the reaction of carbon - containing solvents (like some chlorinated hydrocarbons) with oxygen (from the air) during the high - temperature welding process.

Answer:

phosgene gas