A mixture of Oxygen and nitrogen oxide is used as a medical anaesthesia gas.

The correct option is A True

Anaesthesia gas:

• Medical gases are gases used in medical procedures. Some are used for treatment, some for anesthesia, and some for driving medical devices and tools.
• There are 7 kinds of gases commonly used: $\mathrm{Oxygen},\mathrm{Nitrogen},\mathrm{Nitrous}\mathrm{oxide},\mathrm{Argon},\mathrm{Helium},\mathrm{Carbon}\mathrm{dioxide},\mathrm{and}\mathrm{Compressed}\mathrm{air}$.
• Inhalation of a small amount of $\mathrm{Nitrous}\mathrm{oxide}$ has an anesthetic and analgesic effect, but a large amount of inhalation can suffocate people.
• Medically, a mixture of $\mathrm{Nitrous}\mathrm{oxide}$ and $\mathrm{Oxygen}$ is used as an anesthetic agent, and anesthesia is inhaled by the patient through a closed manner or a ventilator.

Thus, the given statement is True. I.e., A mixture of Oxygen and nitrogen oxide is used as a medical anaesthesia gas.