Which of the following gases is commonly used as an anaesthetic?

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Nitrous oxide ( N ₂ O ) is a colourless, non-flammable gas with a slightly sweet odour and taste. It is commonly known as laughing gas and is widely used in medical and dental procedures for its anaesthetic and analgesic properties. The other gases, N ₂ , CO ₂ , and CH ₄ , are not used as anaesthetics. Answer: N ₂ O