Chemistry Physical Properties Of NO2 Log in to track progress It is reddish-brown gas. It is easily liquefied into a yellow liquid. It turns damp blue litmus paper red. It is heavier than air. It is poisonous. It has an irritating smell. ← Previous Nitrogen (IV) Oxide NO2 Next → Chemical Properties Of NO2 Leave a comment Cancel replyYou must be logged in to post a comment.