इनमें से कौन सी गैस रंगहीन और गंधहीन नहीं है? A. नाइट्रोजन B. क्लोरीन C. हाइड्रोजन D. ऑक्सीजन

Nitrogen, hydrogen and oxygen are all colourless and odourless gases. Chlorine is the exception: it is a greenish-yellow gas with a sharp, pungent, choking smell (the smell noticed near bleach or swimming pools). So chlorine is the gas that is not colourless and odourless.